diff --git a/toolchain/check/cpp/generate_ast.cpp b/toolchain/check/cpp/generate_ast.cpp
index 2240dfa35ebc..9a1204772f4b 100644
--- a/toolchain/check/cpp/generate_ast.cpp
+++ b/toolchain/check/cpp/generate_ast.cpp
@@ -339,7 +339,7 @@ class GenerateASTAction : public clang::ASTFrontendAction {
 
  protected:
   auto CreateASTConsumer(clang::CompilerInstance& clang_instance,
-                         llvm::StringRef file)
+                         llvm::StringRef /*file*/)
       -> std::unique_ptr<clang::ASTConsumer> override {
     auto& cpp_file = *context_->sem_ir().cpp_file();
     if (!cpp_file.llvm_context()) {
@@ -347,7 +347,7 @@ class GenerateASTAction : public clang::ASTFrontendAction {
     }
     auto code_generator =
         std::unique_ptr<clang::CodeGenerator>(clang::CreateLLVMCodeGen(
-            cpp_file.diagnostics(), file,
+            cpp_file.diagnostics(), context_->sem_ir().filename(),
             clang_instance.getVirtualFileSystemPtr(),
             clang_instance.getHeaderSearchOpts(),
             clang_instance.getPreprocessorOpts(),
diff --git a/toolchain/driver/testdata/compile/optimize/clang_no_optimize_twice.carbon b/toolchain/driver/testdata/compile/optimize/clang_no_optimize_twice.carbon
index 84be1aae0675..d89462955dcd 100644
--- a/toolchain/driver/testdata/compile/optimize/clang_no_optimize_twice.carbon
+++ b/toolchain/driver/testdata/compile/optimize/clang_no_optimize_twice.carbon
@@ -33,29 +33,29 @@ fn Call() -> i32 {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_Z1fv = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
-// CHECK:STDOUT: define i32 @_CCall.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %g.call = call i32 @_Z1gv(), !dbg !16
-// CHECK:STDOUT:   ret i32 %g.call, !dbg !17
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef i32 @_Z1gv() #1 {
+// CHECK:STDOUT: define dso_local noundef i32 @_Z1gv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %call = call noundef i32 @_Z1fv()
 // CHECK:STDOUT:   ret i32 %call
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_Z1fv() #2 comdat {
+// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_Z1fv() #1 comdat {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 42
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { noinline nounwind optnone }
-// CHECK:STDOUT: attributes #1 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: noinline nounwind optnone
+// CHECK:STDOUT: define i32 @_CCall.Main() #2 !dbg !12 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %g.call = call i32 @_Z1gv(), !dbg !16
+// CHECK:STDOUT:   ret i32 %g.call, !dbg !17
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { noinline nounwind optnone }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -64,7 +64,7 @@ fn Call() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/context.cpp b/toolchain/lower/context.cpp
index 2b9abd99ef43..74f4d71817ee 100644
--- a/toolchain/lower/context.cpp
+++ b/toolchain/lower/context.cpp
@@ -18,17 +18,24 @@ Context::Context(
     llvm::LLVMContext* llvm_context,
     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> fs, bool want_debug_info,
     const Parse::GetTreeAndSubtreesStore* tree_and_subtrees_getters,
-    llvm::StringRef module_name, int total_ir_count,
-    Lower::OptimizationLevel opt_level, llvm::raw_ostream* vlog_stream)
+    clang::CodeGenerator* clang_code_generator, llvm::StringRef module_name,
+    int total_ir_count, Lower::OptimizationLevel opt_level,
+    llvm::raw_ostream* vlog_stream)
     : llvm_context_(llvm_context),
-      llvm_module_(std::make_unique<llvm::Module>(module_name, *llvm_context)),
+      clang_code_generator_(clang_code_generator),
+      llvm_module_owner_(
+          clang_code_generator_
+              ? nullptr
+              : std::make_unique<llvm::Module>(module_name, *llvm_context)),
+      llvm_module_(llvm_module_owner_ ? llvm_module_owner_.get()
+                                      : clang_code_generator_->GetModule()),
       file_system_(std::move(fs)),
       opt_level_(opt_level),
       di_builder_(*llvm_module_),
-      di_compile_unit_(
-          want_debug_info
-              ? BuildDICompileUnit(module_name, *llvm_module_, di_builder_)
-              : nullptr),
+      di_compile_unit_(want_debug_info
+                           ? BuildDICompileUnit(llvm_module_->getName(),
+                                                *llvm_module_, di_builder_)
+                           : nullptr),
       tree_and_subtrees_getters_(tree_and_subtrees_getters),
       vlog_stream_(vlog_stream),
       total_ir_count_(total_ir_count),
@@ -65,7 +72,9 @@ auto Context::Finalize() && -> std::unique_ptr<llvm::Module> {
     }
   }
 
-  return std::move(llvm_module_);
+  return clang_code_generator_ ? std::unique_ptr<llvm::Module>(
+                                     clang_code_generator_->ReleaseModule())
+                               : std::move(llvm_module_owner_);
 }
 
 auto Context::BuildDICompileUnit(llvm::StringRef module_name,
diff --git a/toolchain/lower/context.h b/toolchain/lower/context.h
index 13092c2b9db8..4a320ea3e6b0 100644
--- a/toolchain/lower/context.h
+++ b/toolchain/lower/context.h
@@ -49,8 +49,9 @@ class Context {
       llvm::LLVMContext* llvm_context,
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> fs, bool want_debug_info,
       const Parse::GetTreeAndSubtreesStore* tree_and_subtrees_getters,
-      llvm::StringRef module_name, int total_ir_count,
-      Lower::OptimizationLevel opt_level, llvm::raw_ostream* vlog_stream);
+      clang::CodeGenerator* code_generator, llvm::StringRef module_name,
+      int total_ir_count, Lower::OptimizationLevel opt_level,
+      llvm::raw_ostream* vlog_stream);
 
   // Gets or creates the `FileContext` for a given SemIR file. If an
   // `inst_namer` is specified the first time this is called for a file, it will
@@ -145,7 +146,9 @@ class Context {
 
   // State for building the LLVM IR.
   llvm::LLVMContext* llvm_context_;
-  std::unique_ptr<llvm::Module> llvm_module_;
+  clang::CodeGenerator* clang_code_generator_;
+  std::unique_ptr<llvm::Module> llvm_module_owner_;
+  llvm::Module* llvm_module_;
 
   // The filesystem for source code.
   llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> file_system_;
diff --git a/toolchain/lower/file_context.cpp b/toolchain/lower/file_context.cpp
index 9b389b7cfa8d..a0b617d366d2 100644
--- a/toolchain/lower/file_context.cpp
+++ b/toolchain/lower/file_context.cpp
@@ -163,11 +163,6 @@ auto FileContext::Finalize() -> void {
     // const-correct.
     cpp_code_generator_->HandleTranslationUnit(
         const_cast<clang::ASTContext&>(cpp_file()->ast_context()));
-    bool link_error = llvm::Linker::linkModules(
-        /*Dest=*/llvm_module(),
-        /*Src=*/std::unique_ptr<llvm::Module>(
-            cpp_code_generator_->ReleaseModule()));
-    CARBON_CHECK(!link_error);
   }
 
   // Find equivalent specifics (from the same generic), replace all uses and
@@ -601,20 +596,17 @@ auto FileContext::FunctionTypeInfoBuilder::GetLoweredTypes(
 }
 
 auto FileContext::HandleReferencedCppFunction(clang::FunctionDecl* cpp_decl)
-    -> void {
-  clang::FunctionDecl* cpp_def = cpp_decl->getDefinition();
-  if (!cpp_def) {
-    return;
-  }
-
+    -> llvm::Function* {
   // Create the LLVM function (`CodeGenModule::GetOrCreateLLVMFunction()`)
   // so that code generation (`CodeGenModule::EmitGlobal()`) would see this
   // function name (`CodeGenModule::getMangledName()`), and will generate
   // its definition.
-  llvm::Constant* function_address =
-      cpp_code_generator_->GetAddrOfGlobal(CreateGlobalDecl(cpp_def),
-                                           /*isForDefinition=*/false);
+  auto* function_address = dyn_cast<llvm::Function>(
+      cpp_code_generator_->GetAddrOfGlobal(CreateGlobalDecl(cpp_decl),
+                                           /*isForDefinition=*/false));
   CARBON_CHECK(function_address);
+
+  return function_address;
 }
 
 auto FileContext::HandleReferencedSpecificFunction(
@@ -697,41 +689,40 @@ auto FileContext::BuildFunctionDecl(SemIR::FunctionId function_id,
              .llvm_function = existing}};
   }
 
+  llvm::Function* llvm_function;
   // If this is a C++ function, tell Clang that we referenced it.
   if (auto clang_decl_id = sem_ir().functions().Get(function_id).clang_decl_id;
       clang_decl_id.has_value()) {
     CARBON_CHECK(!specific_id.has_value(),
                  "Specific functions cannot have C++ definitions");
-    HandleReferencedCppFunction(
+    llvm_function = HandleReferencedCppFunction(
         sem_ir().clang_decls().Get(clang_decl_id).key.decl->getAsFunction());
-    // TODO: Check that the signature and mangling generated by Clang and the
-    // one we generated are the same.
-  }
+  } else {
+    // If this is a specific function, we may need to do additional work to emit
+    // its definition.
+    if (specific_id.has_value()) {
+      HandleReferencedSpecificFunction(function_id, specific_id,
+                                       function_type_info.type);
+    }
 
-  // If this is a specific function, we may need to do additional work to emit
-  // its definition.
-  if (specific_id.has_value()) {
-    HandleReferencedSpecificFunction(function_id, specific_id,
-                                     function_type_info.type);
-  }
+    llvm_function = llvm::Function::Create(function_type_info.type, linkage,
+                                           mangled_name, llvm_module());
 
-  auto* llvm_function = llvm::Function::Create(function_type_info.type, linkage,
-                                               mangled_name, llvm_module());
+    CARBON_CHECK(llvm_function->getName() == mangled_name,
+                 "Mangled name collision: {0}", mangled_name);
 
-  CARBON_CHECK(llvm_function->getName() == mangled_name,
-               "Mangled name collision: {0}", mangled_name);
-
-  // Set up parameters and the return slot.
-  for (auto [inst_id, arg] :
-       llvm::zip_equal(function_type_info.lowered_param_pattern_ids,
-                       llvm_function->args())) {
-    arg.setName(sem_ir().names().GetIRBaseName(
-        SemIR::GetPrettyNameFromPatternId(sem_ir(), inst_id)));
-  }
-  if (function_type_info.sret_type != nullptr) {
-    auto& return_arg = *llvm_function->args().begin();
-    return_arg.addAttr(llvm::Attribute::getWithStructRetType(
-        llvm_context(), function_type_info.sret_type));
+    // Set up parameters and the return slot.
+    for (auto [inst_id, arg] :
+         llvm::zip_equal(function_type_info.lowered_param_pattern_ids,
+                         llvm_function->args())) {
+      arg.setName(sem_ir().names().GetIRBaseName(
+          SemIR::GetPrettyNameFromPatternId(sem_ir(), inst_id)));
+    }
+    if (function_type_info.sret_type != nullptr) {
+      auto& return_arg = *llvm_function->args().begin();
+      return_arg.addAttr(llvm::Attribute::getWithStructRetType(
+          llvm_context(), function_type_info.sret_type));
+    }
   }
 
   return {{.type = function_type_info.type,
diff --git a/toolchain/lower/file_context.h b/toolchain/lower/file_context.h
index b0f8618bdf45..0e01be384f1b 100644
--- a/toolchain/lower/file_context.h
+++ b/toolchain/lower/file_context.h
@@ -180,7 +180,8 @@ class FileContext {
  private:
   // Notes that a C++ function has been referenced for the first time, so we
   // should ask Clang to generate a definition for it if possible.
-  auto HandleReferencedCppFunction(clang::FunctionDecl* cpp_decl) -> void;
+  auto HandleReferencedCppFunction(clang::FunctionDecl* cpp_decl)
+      -> llvm::Function*;
 
   // Notes that a specific function has been referenced for the first time.
   // Updates the fingerprint to include the function's type, and adds the
diff --git a/toolchain/lower/lower.cpp b/toolchain/lower/lower.cpp
index 5a1ce01a8539..7d61a3416379 100644
--- a/toolchain/lower/lower.cpp
+++ b/toolchain/lower/lower.cpp
@@ -20,9 +20,12 @@ auto LowerToLLVM(
     const Parse::GetTreeAndSubtreesStore& tree_and_subtrees_getters,
     const SemIR::File& sem_ir, int total_ir_count,
     const LowerToLLVMOptions& options) -> std::unique_ptr<llvm::Module> {
-  Context context(&llvm_context, std::move(fs), options.want_debug_info,
-                  &tree_and_subtrees_getters, sem_ir.filename(), total_ir_count,
-                  options.opt_level, options.vlog_stream);
+  Context context(
+      &llvm_context, std::move(fs), options.want_debug_info,
+      &tree_and_subtrees_getters,
+      sem_ir.cpp_file() ? sem_ir.cpp_file()->GetCodeGenerator() : nullptr,
+      sem_ir.filename(), total_ir_count, options.opt_level,
+      options.vlog_stream);
 
   // TODO: Consider disabling instruction naming by default if we're not
   // producing textual LLVM IR.
diff --git a/toolchain/lower/testdata/interop/cpp/base.carbon b/toolchain/lower/testdata/interop/cpp/base.carbon
index ab8575330115..f38e4a4a6a59 100644
--- a/toolchain/lower/testdata/interop/cpp/base.carbon
+++ b/toolchain/lower/testdata/interop/cpp/base.carbon
@@ -89,7 +89,7 @@ fn Call(b: Cpp.B*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -136,7 +136,7 @@ fn Call(b: Cpp.B*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -188,7 +188,7 @@ fn Call(b: Cpp.B*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/clang_code_generator_callbacks.carbon b/toolchain/lower/testdata/interop/cpp/clang_code_generator_callbacks.carbon
index 70a9f2245b1b..60f8ccdf0fb0 100644
--- a/toolchain/lower/testdata/interop/cpp/clang_code_generator_callbacks.carbon
+++ b/toolchain/lower/testdata/interop/cpp/clang_code_generator_callbacks.carbon
@@ -81,7 +81,6 @@ void f2() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZN2t3IiE1iE = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: @llvm.compiler.used = appending global [1 x ptr] [ptr @_ZN2t24funcEv], section "llvm.metadata"
 // CHECK:STDOUT: @a = external global [10 x i8], align 1
 // CHECK:STDOUT: @b = dso_local global ptr @a, align 8
 // CHECK:STDOUT: @_ZN2t3IiE1iE = linkonce_odr dso_local global i32 0, comdat, align 4
@@ -89,6 +88,7 @@ void f2() {
 // CHECK:STDOUT: @_ZTI2t1 = dso_local constant { ptr, ptr } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), ptr @_ZTS2t1 }, align 8
 // CHECK:STDOUT: @_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr]
 // CHECK:STDOUT: @_ZTS2t1 = dso_local constant [4 x i8] c"2t1\00", align 1
+// CHECK:STDOUT: @llvm.compiler.used = appending global [1 x ptr] [ptr @_ZN2t24funcEv], section "llvm.metadata"
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_ZN2t12f1Ev(ptr noundef nonnull align 8 dereferenceable(8) %this) unnamed_addr #0 align 2 {
@@ -100,19 +100,19 @@ void f2() {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN2t24funcEv(ptr noundef nonnull align 1 dereferenceable(1) %this) #0 comdat align 2 {
+// CHECK:STDOUT: define dso_local noundef i32 @_Z1fv() #0 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !15
-// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   ret void
+// CHECK:STDOUT:   %0 = load i32, ptr getelementptr inbounds ([10 x %struct.S], ptr @a, i64 0, i64 3), align 4, !tbaa !15
+// CHECK:STDOUT:   ret i32 %0
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define dso_local noundef i32 @_Z1fv() #0 {
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN2t24funcEv(ptr noundef nonnull align 1 dereferenceable(1) %this) #0 comdat align 2 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %0 = load i32, ptr getelementptr inbounds ([10 x %struct.S], ptr @a, i64 0, i64 3), align 4, !tbaa !17
-// CHECK:STDOUT:   ret i32 %0
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !17
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
@@ -131,7 +131,7 @@ void f2() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -143,7 +143,7 @@ void f2() {
 // CHECK:STDOUT: !12 = !{!13, !13, i64 0}
 // CHECK:STDOUT: !13 = !{!"p1 _ZTS2t1", !14, i64 0}
 // CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
-// CHECK:STDOUT: !16 = !{!"p1 _ZTS2t2", !14, i64 0}
-// CHECK:STDOUT: !17 = !{!18, !9, i64 0}
-// CHECK:STDOUT: !18 = !{!"_ZTS1S", !9, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !9, i64 0}
+// CHECK:STDOUT: !16 = !{!"_ZTS1S", !9, i64 0}
+// CHECK:STDOUT: !17 = !{!18, !18, i64 0}
+// CHECK:STDOUT: !18 = !{!"p1 _ZTS2t2", !14, i64 0}
diff --git a/toolchain/lower/testdata/interop/cpp/constructor.carbon b/toolchain/lower/testdata/interop/cpp/constructor.carbon
index 058e539b8859..4e7dbf7ad776 100644
--- a/toolchain/lower/testdata/interop/cpp/constructor.carbon
+++ b/toolchain/lower/testdata/interop/cpp/constructor.carbon
@@ -89,45 +89,45 @@ fn F() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZN1CC2Ev = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_26.1.temp = alloca [8 x i8], align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_26.1.temp), !dbg !15
-// CHECK:STDOUT:   call void @_ZN1CC1Ev.carbon_thunk(ptr %.loc7_26.1.temp), !dbg !15
-// CHECK:STDOUT:   ret void, !dbg !16
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZN1CC1Ev.carbon_thunk(ptr noundef %return) #2 {
+// CHECK:STDOUT: define dso_local void @_ZN1CC1Ev.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !17
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !17
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_ZN1CC2Ev(ptr noundef nonnull align 4 dereferenceable(8) %0)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1CC2Ev(ptr noundef nonnull align 4 dereferenceable(8) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1CC2Ev(ptr noundef nonnull align 4 dereferenceable(8) %this) unnamed_addr #1 comdat align 2 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !17
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
 // CHECK:STDOUT:   %x_ = getelementptr inbounds nuw %class.C, ptr %this1, i32 0, i32 0
-// CHECK:STDOUT:   store i32 8, ptr %x_, align 4, !tbaa !20
+// CHECK:STDOUT:   store i32 8, ptr %x_, align 4, !tbaa !15
 // CHECK:STDOUT:   %y_ = getelementptr inbounds nuw %class.C, ptr %this1, i32 0, i32 1
-// CHECK:STDOUT:   store i32 9, ptr %y_, align 4, !tbaa !22
+// CHECK:STDOUT:   store i32 9, ptr %y_, align 4, !tbaa !17
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF.Main() #2 !dbg !18 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_26.1.temp = alloca [8 x i8], align 1, !dbg !21
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_26.1.temp), !dbg !21
+// CHECK:STDOUT:   call void @_ZN1CC1Ev.carbon_thunk(ptr %.loc7_26.1.temp), !dbg !21
+// CHECK:STDOUT:   ret void, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -136,7 +136,7 @@ fn F() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -145,61 +145,61 @@ fn F() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 18, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !17 = !{!18, !18, i64 0}
-// CHECK:STDOUT: !18 = !{!"p1 _ZTS1C", !19, i64 0}
-// CHECK:STDOUT: !19 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !20 = !{!21, !9, i64 0}
-// CHECK:STDOUT: !21 = !{!"_ZTS1C", !9, i64 0, !9, i64 4}
-// CHECK:STDOUT: !22 = !{!21, !9, i64 4}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !9, i64 0}
+// CHECK:STDOUT: !16 = !{!"_ZTS1C", !9, i64 0, !9, i64 4}
+// CHECK:STDOUT: !17 = !{!16, !9, i64 4}
+// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !7, line: 6, type: !19, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
+// CHECK:STDOUT: !20 = !{null}
+// CHECK:STDOUT: !21 = !DILocation(line: 7, column: 18, scope: !18)
+// CHECK:STDOUT: !22 = !DILocation(line: 6, column: 1, scope: !18)
 // CHECK:STDOUT: ; ModuleID = 'call_copy.carbon'
 // CHECK:STDOUT: source_filename = "call_copy.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCopy.Main(ptr sret([4 x i8]) %return, ptr %c) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_10.1.temp = alloca [4 x i8], align 1, !dbg !18
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_10.1.temp), !dbg !18
-// CHECK:STDOUT:   call void @_ZN4CopyC1ERKS_.carbon_thunk(ptr %c, ptr %return), !dbg !18
-// CHECK:STDOUT:   ret void, !dbg !19
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define void @"_COp:thunk.Copy.Cpp"(ptr sret([4 x i8]) %return, ptr %self) #1 !dbg !20 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_ZN4CopyC1ERKS_.carbon_thunk(ptr %self, ptr %return), !dbg !23
-// CHECK:STDOUT:   ret void, !dbg !23
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #2
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZN4CopyC1ERKS_.carbon_thunk(ptr noundef %0, ptr noundef %return) #3 {
+// CHECK:STDOUT: define dso_local void @_ZN4CopyC1ERKS_.carbon_thunk(ptr noundef %0, ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !24
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !24
-// CHECK:STDOUT:   %1 = load ptr, ptr %return.addr, align 8, !tbaa !24
-// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !24
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_ZN4CopyC1ERKS_(ptr noundef nonnull align 4 dereferenceable(4) %1, ptr noundef nonnull align 4 dereferenceable(4) %2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN4CopyC1ERKS_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) unnamed_addr #4
+// CHECK:STDOUT: declare void @_ZN4CopyC1ERKS_(ptr noundef nonnull align 4 dereferenceable(4), ptr noundef nonnull align 4 dereferenceable(4)) unnamed_addr #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline nounwind }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCopy.Main(ptr sret([4 x i8]) %return, ptr %c) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_10.1.temp = alloca [4 x i8], align 1, !dbg !21
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_10.1.temp), !dbg !21
+// CHECK:STDOUT:   call void @_ZN4CopyC1ERKS_.carbon_thunk(ptr %c, ptr %return), !dbg !21
+// CHECK:STDOUT:   ret void, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_COp:thunk.Copy.Cpp"(ptr sret([4 x i8]) %return, ptr %self) #3 !dbg !23 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN4CopyC1ERKS_.carbon_thunk(ptr %self, ptr %return), !dbg !26
+// CHECK:STDOUT:   ret void, !dbg !26
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #4
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -208,7 +208,7 @@ fn F() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -217,21 +217,21 @@ fn F() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Copy", linkageName: "_CCopy.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 7, column: 10, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Copy.Cpp", scope: null, file: !7, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !21)
-// CHECK:STDOUT: !21 = !{!22}
-// CHECK:STDOUT: !22 = !DILocalVariable(arg: 1, scope: !20, type: !15)
-// CHECK:STDOUT: !23 = !DILocation(line: 0, scope: !20)
-// CHECK:STDOUT: !24 = !{!25, !25, i64 0}
-// CHECK:STDOUT: !25 = !{!"p1 _ZTS4Copy", !26, i64 0}
-// CHECK:STDOUT: !26 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS4Copy", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "Copy", linkageName: "_CCopy.Main", scope: null, file: !7, line: 6, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18, !18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !19 = !{!20}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocation(line: 7, column: 10, scope: !15)
+// CHECK:STDOUT: !22 = !DILocation(line: 7, column: 3, scope: !15)
+// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "Op", linkageName: "_COp:thunk.Copy.Cpp", scope: null, file: !7, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !24)
+// CHECK:STDOUT: !24 = !{!25}
+// CHECK:STDOUT: !25 = !DILocalVariable(arg: 1, scope: !23, type: !18)
+// CHECK:STDOUT: !26 = !DILocation(line: 0, scope: !23)
 // CHECK:STDOUT: ; ModuleID = 'call_c1_in_thunk.carbon'
 // CHECK:STDOUT: source_filename = "call_c1_in_thunk.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -241,6 +241,8 @@ fn F() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTV7Derived = comdat any
 // CHECK:STDOUT:
+// CHECK:STDOUT: $_ZTT7Derived = comdat any
+// CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTI7Derived = comdat any
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTS7Derived = comdat any
@@ -250,6 +252,7 @@ fn F() {
 // CHECK:STDOUT: $_ZTS4Base = comdat any
 // CHECK:STDOUT:
 // CHECK:STDOUT: @_ZTV7Derived = linkonce_odr dso_local unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZTI7Derived] }, comdat, align 8
+// CHECK:STDOUT: @_ZTT7Derived = linkonce_odr dso_local unnamed_addr constant [1 x ptr] [ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr] }, ptr @_ZTV7Derived, i32 0, i32 0, i32 3)], comdat, align 8
 // CHECK:STDOUT: @_ZTI7Derived = linkonce_odr dso_local constant { ptr, ptr, i32, i32, ptr, i64 } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv121__vmi_class_type_infoE, i64 2), ptr @_ZTS7Derived, i32 0, i32 1, ptr @_ZTI4Base, i64 -6141 }, comdat, align 8
 // CHECK:STDOUT: @_ZTVN10__cxxabiv121__vmi_class_type_infoE = external global [0 x ptr]
 // CHECK:STDOUT: @_ZTS7Derived = linkonce_odr dso_local constant [9 x i8] c"7Derived\00", comdat, align 1
@@ -257,42 +260,45 @@ fn F() {
 // CHECK:STDOUT: @_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr]
 // CHECK:STDOUT: @_ZTS4Base = linkonce_odr dso_local constant [6 x i8] c"4Base\00", comdat, align 1
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_44.1.temp = alloca [8 x i8], align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_44.1.temp), !dbg !15
-// CHECK:STDOUT:   call void @_ZN7DerivedC1Ev.carbon_thunk(ptr %.loc7_44.1.temp), !dbg !15
-// CHECK:STDOUT:   ret void, !dbg !16
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
-// CHECK:STDOUT: define dso_local void @_ZN7DerivedC1Ev.carbon_thunk(ptr noundef %return) #2 {
+// CHECK:STDOUT: define dso_local void @_ZN7DerivedC1Ev.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !17
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !17
-// CHECK:STDOUT:   call void @_ZN7DerivedC1Ev(ptr noundef nonnull align 8 dereferenceable(8) %0) #0
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   call void @_ZN7DerivedC1Ev(ptr noundef nonnull align 8 dereferenceable(8) %0) #2
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN7DerivedC1Ev(ptr noundef nonnull align 8 dereferenceable(8) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN7DerivedC1Ev(ptr noundef nonnull align 8 dereferenceable(8) %this) unnamed_addr #1 comdat align 2 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !17
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr] }, ptr @_ZTV7Derived, i32 0, i32 0, i32 3), ptr %this1, align 8, !tbaa !20
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr] }, ptr @_ZTV7Derived, i32 0, i32 0, i32 3), ptr %this1, align 8, !tbaa !15
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF.Main() #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_44.1.temp = alloca [8 x i8], align 1, !dbg !20
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_44.1.temp), !dbg !20
+// CHECK:STDOUT:   call void @_ZN7DerivedC1Ev.carbon_thunk(ptr %.loc7_44.1.temp), !dbg !20
+// CHECK:STDOUT:   ret void, !dbg !21
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; uselistorder directives
+// CHECK:STDOUT: uselistorder ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr] }, ptr @_ZTV7Derived, i32 0, i32 0, i32 3), { 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -301,7 +307,7 @@ fn F() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -310,13 +316,13 @@ fn F() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 24, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !17 = !{!18, !18, i64 0}
-// CHECK:STDOUT: !18 = !{!"p1 _ZTS7Derived", !19, i64 0}
-// CHECK:STDOUT: !19 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !20 = !{!21, !21, i64 0}
-// CHECK:STDOUT: !21 = !{!"vtable pointer", !11, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS7Derived", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"vtable pointer", !11, i64 0}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !7, line: 6, type: !18, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{null}
+// CHECK:STDOUT: !20 = !DILocation(line: 7, column: 24, scope: !17)
+// CHECK:STDOUT: !21 = !DILocation(line: 6, column: 1, scope: !17)
diff --git a/toolchain/lower/testdata/interop/cpp/enum.carbon b/toolchain/lower/testdata/interop/cpp/enum.carbon
index 153a97c8b42a..6e1379076799 100644
--- a/toolchain/lower/testdata/interop/cpp/enum.carbon
+++ b/toolchain/lower/testdata/interop/cpp/enum.carbon
@@ -87,63 +87,63 @@ fn Call() {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPass.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_16.1.temp = alloca i16, align 2, !dbg !15
-// CHECK:STDOUT:   %.loc8_16.1.temp = alloca i16, align 2, !dbg !16
-// CHECK:STDOUT:   %.loc9_16.1.temp = alloca i16, align 2, !dbg !17
-// CHECK:STDOUT:   %.loc10_16.1.temp = alloca i16, align 2, !dbg !18
-// CHECK:STDOUT:   %.loc11_18.1.temp = alloca i16, align 2, !dbg !19
-// CHECK:STDOUT:   %.loc12_18.1.temp = alloca i16, align 2, !dbg !20
-// CHECK:STDOUT:   %.loc13_18.1.temp = alloca i16, align 2, !dbg !21
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_16.1.temp), !dbg !15
-// CHECK:STDOUT:   store i16 0, ptr %.loc7_16.1.temp, align 2, !dbg !15
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc7_16.1.temp), !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc8_16.1.temp), !dbg !16
-// CHECK:STDOUT:   store i16 0, ptr %.loc8_16.1.temp, align 2, !dbg !16
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc8_16.1.temp), !dbg !23
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_16.1.temp), !dbg !17
-// CHECK:STDOUT:   store i16 7, ptr %.loc9_16.1.temp, align 2, !dbg !17
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc9_16.1.temp), !dbg !24
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc10_16.1.temp), !dbg !18
-// CHECK:STDOUT:   store i16 8, ptr %.loc10_16.1.temp, align 2, !dbg !18
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc10_16.1.temp), !dbg !25
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc11_18.1.temp), !dbg !19
-// CHECK:STDOUT:   store i16 0, ptr %.loc11_18.1.temp, align 2, !dbg !19
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc11_18.1.temp), !dbg !26
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_18.1.temp), !dbg !20
-// CHECK:STDOUT:   store i16 7, ptr %.loc12_18.1.temp, align 2, !dbg !20
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc12_18.1.temp), !dbg !27
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc13_18.1.temp), !dbg !21
-// CHECK:STDOUT:   store i16 8, ptr %.loc13_18.1.temp, align 2, !dbg !21
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc13_18.1.temp), !dbg !28
-// CHECK:STDOUT:   ret void, !dbg !29
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZN1C1FENS_1EE.carbon_thunk(ptr noundef %0) #2 {
+// CHECK:STDOUT: define dso_local void @_ZN1C1FENS_1EE.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !30
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !30
-// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !32
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !14
 // CHECK:STDOUT:   call void @_ZN1C1FENS_1EE(i16 noundef signext %2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1C1FENS_1EE(i16 noundef signext) #3
+// CHECK:STDOUT: declare void @_ZN1C1FENS_1EE(i16 noundef signext) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPass.Main() #2 !dbg !16 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_16.1.temp = alloca i16, align 2, !dbg !19
+// CHECK:STDOUT:   %.loc8_16.1.temp = alloca i16, align 2, !dbg !20
+// CHECK:STDOUT:   %.loc9_16.1.temp = alloca i16, align 2, !dbg !21
+// CHECK:STDOUT:   %.loc10_16.1.temp = alloca i16, align 2, !dbg !22
+// CHECK:STDOUT:   %.loc11_18.1.temp = alloca i16, align 2, !dbg !23
+// CHECK:STDOUT:   %.loc12_18.1.temp = alloca i16, align 2, !dbg !24
+// CHECK:STDOUT:   %.loc13_18.1.temp = alloca i16, align 2, !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_16.1.temp), !dbg !19
+// CHECK:STDOUT:   store i16 0, ptr %.loc7_16.1.temp, align 2, !dbg !19
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc7_16.1.temp), !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc8_16.1.temp), !dbg !20
+// CHECK:STDOUT:   store i16 0, ptr %.loc8_16.1.temp, align 2, !dbg !20
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc8_16.1.temp), !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_16.1.temp), !dbg !21
+// CHECK:STDOUT:   store i16 7, ptr %.loc9_16.1.temp, align 2, !dbg !21
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc9_16.1.temp), !dbg !28
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc10_16.1.temp), !dbg !22
+// CHECK:STDOUT:   store i16 8, ptr %.loc10_16.1.temp, align 2, !dbg !22
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc10_16.1.temp), !dbg !29
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc11_18.1.temp), !dbg !23
+// CHECK:STDOUT:   store i16 0, ptr %.loc11_18.1.temp, align 2, !dbg !23
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc11_18.1.temp), !dbg !30
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_18.1.temp), !dbg !24
+// CHECK:STDOUT:   store i16 7, ptr %.loc12_18.1.temp, align 2, !dbg !24
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc12_18.1.temp), !dbg !31
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc13_18.1.temp), !dbg !25
+// CHECK:STDOUT:   store i16 8, ptr %.loc13_18.1.temp, align 2, !dbg !25
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc13_18.1.temp), !dbg !32
+// CHECK:STDOUT:   ret void, !dbg !33
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 6, 5, 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -152,7 +152,7 @@ fn Call() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -161,79 +161,79 @@ fn Call() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Pass", linkageName: "_CPass.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 11, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 8, column: 11, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 9, column: 11, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 10, column: 11, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 11, column: 11, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 12, column: 11, scope: !12)
-// CHECK:STDOUT: !21 = !DILocation(line: 13, column: 11, scope: !12)
-// CHECK:STDOUT: !22 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !23 = !DILocation(line: 8, column: 3, scope: !12)
-// CHECK:STDOUT: !24 = !DILocation(line: 9, column: 3, scope: !12)
-// CHECK:STDOUT: !25 = !DILocation(line: 10, column: 3, scope: !12)
-// CHECK:STDOUT: !26 = !DILocation(line: 11, column: 3, scope: !12)
-// CHECK:STDOUT: !27 = !DILocation(line: 12, column: 3, scope: !12)
-// CHECK:STDOUT: !28 = !DILocation(line: 13, column: 3, scope: !12)
-// CHECK:STDOUT: !29 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !30 = !{!31, !31, i64 0}
-// CHECK:STDOUT: !31 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !32 = !{!33, !33, i64 0}
-// CHECK:STDOUT: !33 = !{!"_ZTSN1C1EE", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !14 = !{!15, !15, i64 0}
+// CHECK:STDOUT: !15 = !{!"_ZTSN1C1EE", !10, i64 0}
+// CHECK:STDOUT: !16 = distinct !DISubprogram(name: "Pass", linkageName: "_CPass.Main", scope: null, file: !7, line: 6, type: !17, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !17 = !DISubroutineType(types: !18)
+// CHECK:STDOUT: !18 = !{null}
+// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 11, scope: !16)
+// CHECK:STDOUT: !20 = !DILocation(line: 8, column: 11, scope: !16)
+// CHECK:STDOUT: !21 = !DILocation(line: 9, column: 11, scope: !16)
+// CHECK:STDOUT: !22 = !DILocation(line: 10, column: 11, scope: !16)
+// CHECK:STDOUT: !23 = !DILocation(line: 11, column: 11, scope: !16)
+// CHECK:STDOUT: !24 = !DILocation(line: 12, column: 11, scope: !16)
+// CHECK:STDOUT: !25 = !DILocation(line: 13, column: 11, scope: !16)
+// CHECK:STDOUT: !26 = !DILocation(line: 7, column: 3, scope: !16)
+// CHECK:STDOUT: !27 = !DILocation(line: 8, column: 3, scope: !16)
+// CHECK:STDOUT: !28 = !DILocation(line: 9, column: 3, scope: !16)
+// CHECK:STDOUT: !29 = !DILocation(line: 10, column: 3, scope: !16)
+// CHECK:STDOUT: !30 = !DILocation(line: 11, column: 3, scope: !16)
+// CHECK:STDOUT: !31 = !DILocation(line: 12, column: 3, scope: !16)
+// CHECK:STDOUT: !32 = !DILocation(line: 13, column: 3, scope: !16)
+// CHECK:STDOUT: !33 = !DILocation(line: 6, column: 1, scope: !16)
 // CHECK:STDOUT: ; ModuleID = 'convert.carbon'
 // CHECK:STDOUT: source_filename = "convert.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_CTakeI16.Main(i16)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassEnum.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_CTakeI16.Main(i16 7), !dbg !15
-// CHECK:STDOUT:   ret void, !dbg !16
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CConvertEnumToI16.Main(i16 %e) #0 !dbg !17 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_CTakeI16.Main(i16 %e), !dbg !23
-// CHECK:STDOUT:   ret void, !dbg !24
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CConvertI16ToEnum.Main(i16 %n) #0 !dbg !25 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc17_13.3.temp = alloca i16, align 2, !dbg !28
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_13.3.temp), !dbg !28
-// CHECK:STDOUT:   store i16 %n, ptr %.loc17_13.3.temp, align 2, !dbg !28
-// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc17_13.3.temp), !dbg !29
-// CHECK:STDOUT:   ret void, !dbg !30
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZN1C1FENS_1EE.carbon_thunk(ptr noundef %0) #2 {
+// CHECK:STDOUT: define dso_local void @_ZN1C1FENS_1EE.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !31
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !31
-// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !33
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !14
 // CHECK:STDOUT:   call void @_ZN1C1FENS_1EE(i16 noundef signext %2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1C1FENS_1EE(i16 noundef signext) #3
+// CHECK:STDOUT: declare void @_ZN1C1FENS_1EE(i16 noundef signext) #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: declare void @_CTakeI16.Main(i16)
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassEnum.Main() #2 !dbg !16 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_CTakeI16.Main(i16 7), !dbg !19
+// CHECK:STDOUT:   ret void, !dbg !20
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CConvertEnumToI16.Main(i16 %e) #2 !dbg !21 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_CTakeI16.Main(i16 %e), !dbg !27
+// CHECK:STDOUT:   ret void, !dbg !28
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CConvertI16ToEnum.Main(i16 %n) #2 !dbg !29 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc17_13.3.temp = alloca i16, align 2, !dbg !32
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_13.3.temp), !dbg !32
+// CHECK:STDOUT:   store i16 %n, ptr %.loc17_13.3.temp, align 2, !dbg !32
+// CHECK:STDOUT:   call void @_ZN1C1FENS_1EE.carbon_thunk(ptr %.loc17_13.3.temp), !dbg !33
+// CHECK:STDOUT:   ret void, !dbg !34
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -242,7 +242,7 @@ fn Call() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -251,29 +251,29 @@ fn Call() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassEnum", linkageName: "_CPassEnum.Main", scope: null, file: !7, line: 8, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 9, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 8, column: 1, scope: !12)
-// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "ConvertEnumToI16", linkageName: "_CConvertEnumToI16.Main", scope: null, file: !7, line: 12, type: !18, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !21)
-// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
-// CHECK:STDOUT: !19 = !{null, !20}
-// CHECK:STDOUT: !20 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !21 = !{!22}
-// CHECK:STDOUT: !22 = !DILocalVariable(arg: 1, scope: !17, type: !20)
-// CHECK:STDOUT: !23 = !DILocation(line: 13, column: 3, scope: !17)
-// CHECK:STDOUT: !24 = !DILocation(line: 12, column: 1, scope: !17)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "ConvertI16ToEnum", linkageName: "_CConvertI16ToEnum.Main", scope: null, file: !7, line: 16, type: !18, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !26)
-// CHECK:STDOUT: !26 = !{!27}
-// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !25, type: !20)
-// CHECK:STDOUT: !28 = !DILocation(line: 17, column: 11, scope: !25)
-// CHECK:STDOUT: !29 = !DILocation(line: 17, column: 3, scope: !25)
-// CHECK:STDOUT: !30 = !DILocation(line: 16, column: 1, scope: !25)
-// CHECK:STDOUT: !31 = !{!32, !32, i64 0}
-// CHECK:STDOUT: !32 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !33 = !{!34, !34, i64 0}
-// CHECK:STDOUT: !34 = !{!"_ZTSN1C1EE", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !14 = !{!15, !15, i64 0}
+// CHECK:STDOUT: !15 = !{!"_ZTSN1C1EE", !10, i64 0}
+// CHECK:STDOUT: !16 = distinct !DISubprogram(name: "PassEnum", linkageName: "_CPassEnum.Main", scope: null, file: !7, line: 8, type: !17, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !17 = !DISubroutineType(types: !18)
+// CHECK:STDOUT: !18 = !{null}
+// CHECK:STDOUT: !19 = !DILocation(line: 9, column: 3, scope: !16)
+// CHECK:STDOUT: !20 = !DILocation(line: 8, column: 1, scope: !16)
+// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "ConvertEnumToI16", linkageName: "_CConvertEnumToI16.Main", scope: null, file: !7, line: 12, type: !22, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !25)
+// CHECK:STDOUT: !22 = !DISubroutineType(types: !23)
+// CHECK:STDOUT: !23 = !{null, !24}
+// CHECK:STDOUT: !24 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !25 = !{!26}
+// CHECK:STDOUT: !26 = !DILocalVariable(arg: 1, scope: !21, type: !24)
+// CHECK:STDOUT: !27 = !DILocation(line: 13, column: 3, scope: !21)
+// CHECK:STDOUT: !28 = !DILocation(line: 12, column: 1, scope: !21)
+// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "ConvertI16ToEnum", linkageName: "_CConvertI16ToEnum.Main", scope: null, file: !7, line: 16, type: !22, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !30)
+// CHECK:STDOUT: !30 = !{!31}
+// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !24)
+// CHECK:STDOUT: !32 = !DILocation(line: 17, column: 11, scope: !29)
+// CHECK:STDOUT: !33 = !DILocation(line: 17, column: 3, scope: !29)
+// CHECK:STDOUT: !34 = !DILocation(line: 16, column: 1, scope: !29)
 // CHECK:STDOUT: ; ModuleID = 'use_bitmask.carbon'
 // CHECK:STDOUT: source_filename = "use_bitmask.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -286,9 +286,10 @@ fn Call() {
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z4Take4Bits(i32)
+// CHECK:STDOUT: declare void @_Z4Take4Bits(i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -297,7 +298,7 @@ fn Call() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/extern_c.carbon b/toolchain/lower/testdata/interop/cpp/extern_c.carbon
index 1afc5bf2b59b..3958466f1be1 100644
--- a/toolchain/lower/testdata/interop/cpp/extern_c.carbon
+++ b/toolchain/lower/testdata/interop/cpp/extern_c.carbon
@@ -114,9 +114,10 @@ fn MyF() {
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @foo()
+// CHECK:STDOUT: declare void @foo() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -125,7 +126,7 @@ fn MyF() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -152,11 +153,12 @@ fn MyF() {
 // CHECK:STDOUT:   ret void, !dbg !17
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @foo()
+// CHECK:STDOUT: declare void @foo() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooi(i32)
+// CHECK:STDOUT: declare void @_Z3fooi(i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -165,7 +167,7 @@ fn MyF() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -203,7 +205,7 @@ fn MyF() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -225,15 +227,8 @@ fn MyF() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %struct.X = type { i8 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CMyF.Main(ptr sret({}) %return, ptr %a, ptr %b) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Zpl1XS_.carbon_thunk(ptr %a, ptr %b, ptr %return), !dbg !19
-// CHECK:STDOUT:   ret void, !dbg !20
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Zpl1XS_.carbon_thunk(ptr noundef %0, ptr noundef %1, ptr noundef %return) #1 {
+// CHECK:STDOUT: define dso_local void @_Zpl1XS_.carbon_thunk(ptr noundef %0, ptr noundef %1, ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %.addr1 = alloca ptr, align 8
@@ -241,21 +236,28 @@ fn MyF() {
 // CHECK:STDOUT:   %agg.tmp = alloca %struct.X, align 1
 // CHECK:STDOUT:   %agg.tmp2 = alloca %struct.X, align 1
 // CHECK:STDOUT:   %undef.agg.tmp = alloca %struct.X, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !21
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   %2 = load ptr, ptr %return.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   %3 = load ptr, ptr %.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   %4 = load ptr, ptr %.addr1, align 8, !tbaa !21
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %2 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %3 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %4 = load ptr, ptr %.addr1, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Zpl1XS_()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Zpl1XS_() #2
+// CHECK:STDOUT: declare void @_Zpl1XS_() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CMyF.Main(ptr sret({}) %return, ptr %a, ptr %b) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Zpl1XS_.carbon_thunk(ptr %a, ptr %b, ptr %return), !dbg !22
+// CHECK:STDOUT:   ret void, !dbg !23
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -264,7 +266,7 @@ fn MyF() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -273,18 +275,18 @@ fn MyF() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "MyF", linkageName: "_CMyF.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15, !15, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17, !18}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocalVariable(arg: 2, scope: !12, type: !15)
-// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 10, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !{!22, !22, i64 0}
-// CHECK:STDOUT: !22 = !{!"p1 _ZTS1X", !23, i64 0}
-// CHECK:STDOUT: !23 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1X", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "MyF", linkageName: "_CMyF.Main", scope: null, file: !7, line: 6, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18, !18, !18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !19 = !{!20, !21}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocalVariable(arg: 2, scope: !15, type: !18)
+// CHECK:STDOUT: !22 = !DILocation(line: 7, column: 10, scope: !15)
+// CHECK:STDOUT: !23 = !DILocation(line: 7, column: 3, scope: !15)
 // CHECK:STDOUT: ; ModuleID = 'import_extern_c_with_asm_label.carbon'
 // CHECK:STDOUT: source_filename = "import_extern_c_with_asm_label.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -297,9 +299,10 @@ fn MyF() {
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @bar()
+// CHECK:STDOUT: declare void @bar() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -308,7 +311,7 @@ fn MyF() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/field.carbon b/toolchain/lower/testdata/interop/cpp/field.carbon
index 8a52ebe75732..97c568afd5b4 100644
--- a/toolchain/lower/testdata/interop/cpp/field.carbon
+++ b/toolchain/lower/testdata/interop/cpp/field.carbon
@@ -138,7 +138,7 @@ fn AccessP(a: Cpp.A) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -191,7 +191,7 @@ fn AccessP(a: Cpp.A) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -243,7 +243,7 @@ fn AccessP(a: Cpp.A) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -296,7 +296,7 @@ fn AccessP(a: Cpp.A) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -349,7 +349,7 @@ fn AccessP(a: Cpp.A) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/function_decl.carbon b/toolchain/lower/testdata/interop/cpp/function_decl.carbon
index 112a351fd515..7af3e469a1f0 100644
--- a/toolchain/lower/testdata/interop/cpp/function_decl.carbon
+++ b/toolchain/lower/testdata/interop/cpp/function_decl.carbon
@@ -144,9 +144,10 @@ fn MyF() -> i32 {
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3foov()
+// CHECK:STDOUT: declare void @_Z3foov() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -155,7 +156,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -199,7 +200,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -222,24 +223,24 @@ fn MyF() -> i32 {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @llvm.compiler.used = appending global [1 x ptr] [ptr @_Z3foov], section "llvm.metadata"
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_Z3foov() #0 comdat {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CMyF.Main() #0 !dbg !12 {
+// CHECK:STDOUT: define void @_CMyF.Main() #1 !dbg !12 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   call void @_Z3foov(), !dbg !15
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_Z3foov() #1 comdat {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @_Z3foov, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -248,7 +249,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -310,7 +311,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -366,7 +367,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -385,8 +386,46 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z13NoReturnValueii.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z13NoReturnValueii(i32 noundef 1, i32 noundef 2)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z13NoReturnValueii(i32 noundef, i32 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z13NoReturnValueii.carbon_thunk1(i32 noundef %a) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %a.addr = alloca i32, align 4
+// CHECK:STDOUT:   store i32 %a, ptr %a.addr, align 4, !tbaa !8
+// CHECK:STDOUT:   %0 = load i32, ptr %a.addr, align 4, !tbaa !8
+// CHECK:STDOUT:   call void @_Z13NoReturnValueii(i32 noundef %0, i32 noundef 2)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef i32 @_Z17SimpleReturnValueii.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %call = call noundef i32 @_Z17SimpleReturnValueii(i32 noundef 1, i32 noundef 2)
+// CHECK:STDOUT:   ret i32 %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef i32 @_Z17SimpleReturnValueii(i32 noundef, i32 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef i32 @_Z17SimpleReturnValueii.carbon_thunk1(i32 noundef %a) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %a.addr = alloca i32, align 4
+// CHECK:STDOUT:   store i32 %a, ptr %a.addr, align 4, !tbaa !8
+// CHECK:STDOUT:   %0 = load i32, ptr %a.addr, align 4, !tbaa !8
+// CHECK:STDOUT:   %call = call noundef i32 @_Z17SimpleReturnValueii(i32 noundef %0, i32 noundef 2)
+// CHECK:STDOUT:   ret i32 %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CMyF.Main() #0 !dbg !12 {
+// CHECK:STDOUT: define i32 @_CMyF.Main() #2 !dbg !12 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %value.var = alloca i32, align 4, !dbg !16
 // CHECK:STDOUT:   call void @_Z13NoReturnValueii.carbon_thunk0(), !dbg !17
@@ -403,50 +442,13 @@ fn MyF() -> i32 {
 // CHECK:STDOUT:   ret i32 %.loc14, !dbg !26
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13NoReturnValueii(i32, i32)
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare i32 @_Z17SimpleReturnValueii(i32, i32)
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13NoReturnValueii.carbon_thunk0() #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z13NoReturnValueii(i32 noundef 1, i32 noundef 2)
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13NoReturnValueii.carbon_thunk1(i32 noundef %a) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %a.addr = alloca i32, align 4
-// CHECK:STDOUT:   store i32 %a, ptr %a.addr, align 4, !tbaa !8
-// CHECK:STDOUT:   %0 = load i32, ptr %a.addr, align 4, !tbaa !8
-// CHECK:STDOUT:   call void @_Z13NoReturnValueii(i32 noundef %0, i32 noundef 2)
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef i32 @_Z17SimpleReturnValueii.carbon_thunk0() #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %call = call noundef i32 @_Z17SimpleReturnValueii(i32 noundef 1, i32 noundef 2)
-// CHECK:STDOUT:   ret i32 %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef i32 @_Z17SimpleReturnValueii.carbon_thunk1(i32 noundef %a) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %a.addr = alloca i32, align 4
-// CHECK:STDOUT:   store i32 %a, ptr %a.addr, align 4, !tbaa !8
-// CHECK:STDOUT:   %0 = load i32, ptr %a.addr, align 4, !tbaa !8
-// CHECK:STDOUT:   %call = call noundef i32 @_Z17SimpleReturnValueii(i32 noundef %0, i32 noundef 2)
-// CHECK:STDOUT:   ret i32 %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -455,7 +457,7 @@ fn MyF() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/function_in_template.carbon b/toolchain/lower/testdata/interop/cpp/function_in_template.carbon
index 35b509806ea3..866b976b5349 100644
--- a/toolchain/lower/testdata/interop/cpp/function_in_template.carbon
+++ b/toolchain/lower/testdata/interop/cpp/function_in_template.carbon
@@ -62,7 +62,7 @@ fn F() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/globals.carbon b/toolchain/lower/testdata/interop/cpp/globals.carbon
index a04fda70d702..e96a99e5a7fe 100644
--- a/toolchain/lower/testdata/interop/cpp/globals.carbon
+++ b/toolchain/lower/testdata/interop/cpp/globals.carbon
@@ -162,6 +162,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: %class.C = type { i8 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: @global = dso_local global %class.C zeroinitializer, align 1
+// CHECK:STDOUT: @global.1 = external global {}
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define void @_CMyF.Main() #0 !dbg !12 {
@@ -178,7 +179,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -200,23 +201,15 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $inline_global = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init, ptr @inline_global }]
-// CHECK:STDOUT: @llvm.used = appending global [1 x ptr] [ptr @inline_global], section "llvm.metadata"
 // CHECK:STDOUT: @inline_global = linkonce_odr dso_local global %struct.C zeroinitializer, comdat, align 1
 // CHECK:STDOUT: @_ZGV13inline_global = linkonce_odr dso_local global i64 0, comdat($inline_global), align 8
 // CHECK:STDOUT: @__dso_handle = external hidden global i8
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCallF.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_ZN1C1fEv(ptr @inline_global), !dbg !15
-// CHECK:STDOUT:   ret void, !dbg !16
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1C1fEv(ptr)
+// CHECK:STDOUT: @inline_global.1 = external global {}
+// CHECK:STDOUT: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init, ptr @inline_global }]
+// CHECK:STDOUT: @llvm.used = appending global [1 x ptr] [ptr @inline_global], section "llvm.metadata"
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: uwtable
-// CHECK:STDOUT: define internal void @__cxx_global_var_init() #1 section ".text.startup" comdat($inline_global) personality ptr @__gxx_personality_v0 {
+// CHECK:STDOUT: define internal void @__cxx_global_var_init() #0 section ".text.startup" comdat($inline_global) personality ptr @__gxx_personality_v0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %exn.slot = alloca ptr, align 8
 // CHECK:STDOUT:   %ehselector.slot = alloca i32, align 4
@@ -225,7 +218,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:   br i1 %guard.uninitialized, label %init.check, label %init.end
 // CHECK:STDOUT:
 // CHECK:STDOUT: init.check:                                       ; preds = %entry
-// CHECK:STDOUT:   %1 = call i32 @__cxa_guard_acquire(ptr @_ZGV13inline_global) #0
+// CHECK:STDOUT:   %1 = call i32 @__cxa_guard_acquire(ptr @_ZGV13inline_global) #1
 // CHECK:STDOUT:   %tobool = icmp ne i32 %1, 0
 // CHECK:STDOUT:   br i1 %tobool, label %init, label %init.end
 // CHECK:STDOUT:
@@ -234,8 +227,8 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:           to label %invoke.cont unwind label %lpad
 // CHECK:STDOUT:
 // CHECK:STDOUT: invoke.cont:                                      ; preds = %init
-// CHECK:STDOUT:   %2 = call i32 @__cxa_atexit(ptr @_ZN1CD1Ev, ptr @inline_global, ptr @__dso_handle) #0
-// CHECK:STDOUT:   call void @__cxa_guard_release(ptr @_ZGV13inline_global) #0
+// CHECK:STDOUT:   %2 = call i32 @__cxa_atexit(ptr @_ZN1CD1Ev, ptr @inline_global, ptr @__dso_handle) #1
+// CHECK:STDOUT:   call void @__cxa_guard_release(ptr @_ZGV13inline_global) #1
 // CHECK:STDOUT:   br label %init.end
 // CHECK:STDOUT:
 // CHECK:STDOUT: init.end:                                         ; preds = %invoke.cont, %init.check, %entry
@@ -248,7 +241,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:   store ptr %4, ptr %exn.slot, align 8
 // CHECK:STDOUT:   %5 = extractvalue { ptr, i32 } %3, 1
 // CHECK:STDOUT:   store i32 %5, ptr %ehselector.slot, align 4
-// CHECK:STDOUT:   call void @__cxa_guard_abort(ptr @_ZGV13inline_global) #0
+// CHECK:STDOUT:   call void @__cxa_guard_abort(ptr @_ZGV13inline_global) #1
 // CHECK:STDOUT:   br label %eh.resume
 // CHECK:STDOUT:
 // CHECK:STDOUT: eh.resume:                                        ; preds = %lpad
@@ -259,30 +252,40 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:   resume { ptr, i32 } %lpad.val1
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare i32 @__gxx_personality_v0(...)
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare i32 @__cxa_guard_acquire(ptr) #0
+// CHECK:STDOUT: declare i32 @__cxa_guard_acquire(ptr) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_ZN1CC1Ev(ptr noundef nonnull align 1 dereferenceable(1)) unnamed_addr #2
 // CHECK:STDOUT:
+// CHECK:STDOUT: declare i32 @__gxx_personality_v0(...)
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: declare void @_ZN1CD1Ev(ptr noundef nonnull align 1 dereferenceable(1)) unnamed_addr #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare i32 @__cxa_atexit(ptr, ptr, ptr) #0
+// CHECK:STDOUT: declare i32 @__cxa_atexit(ptr, ptr, ptr) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare void @__cxa_guard_release(ptr) #0
+// CHECK:STDOUT: declare void @__cxa_guard_abort(ptr) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare void @__cxa_guard_abort(ptr) #0
+// CHECK:STDOUT: declare void @__cxa_guard_release(ptr) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCallF.Main() #1 !dbg !12 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_ZN1C1fEv(ptr @inline_global.1), !dbg !15
+// CHECK:STDOUT:   ret void, !dbg !16
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_ZN1C1fEv(ptr noundef nonnull align 1 dereferenceable(1)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
-// CHECK:STDOUT: uselistorder ptr @inline_global, { 1, 2, 4, 3, 0 }
+// CHECK:STDOUT: uselistorder ptr @inline_global, { 2, 3, 0, 1 }
+// CHECK:STDOUT: uselistorder ptr @_ZGV13inline_global, { 1, 0, 2, 3 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { nounwind }
 // CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #3 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
@@ -293,7 +296,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -318,42 +321,42 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @thread_local_global = dso_local thread_local global i32 0, align 4
 // CHECK:STDOUT: @thread_local_global_with_init = dso_local thread_local global i32 0, align 4
+// CHECK:STDOUT: @thread_local_global.1 = external global i32
+// CHECK:STDOUT: @thread_local_global_with_init.2 = external global i32
 // CHECK:STDOUT: @__tls_guard = internal thread_local global i8 0, align 1
 // CHECK:STDOUT:
 // CHECK:STDOUT: @_ZTH29thread_local_global_with_init = dso_local alias void (), ptr @__tls_init
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CThreadLocalStore.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   store i32 42, ptr @thread_local_global, align 4, !dbg !15
-// CHECK:STDOUT:   ret void, !dbg !16
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CThreadLocalTriggerInit.Main() #0 !dbg !17 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc14 = load i32, ptr @thread_local_global_with_init, align 4, !dbg !21
-// CHECK:STDOUT:   ret i32 %.loc14, !dbg !22
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: uwtable
-// CHECK:STDOUT: define weak_odr hidden noundef ptr @_ZTW19thread_local_global() #1 comdat {
-// CHECK:STDOUT:   %1 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global)
-// CHECK:STDOUT:   ret ptr %1
+// CHECK:STDOUT: define internal void @__cxx_global_var_init() #0 section ".text.startup" {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %call = call noundef i32 @_Z4initv()
+// CHECK:STDOUT:   %0 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global_with_init)
+// CHECK:STDOUT:   store i32 %call, ptr %0, align 4, !tbaa !8
+// CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef i32 @_Z4initv() #1
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
 // CHECK:STDOUT: declare nonnull ptr @llvm.threadlocal.address.p0(ptr nonnull) #2
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: uwtable
-// CHECK:STDOUT: define weak_odr hidden noundef ptr @_ZTW29thread_local_global_with_init() #1 comdat {
-// CHECK:STDOUT:   call void @_ZTH29thread_local_global_with_init()
-// CHECK:STDOUT:   %1 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global_with_init)
-// CHECK:STDOUT:   ret ptr %1
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CThreadLocalStore.Main() #3 !dbg !12 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   store i32 42, ptr @thread_local_global.1, align 4, !dbg !15
+// CHECK:STDOUT:   ret void, !dbg !16
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CThreadLocalTriggerInit.Main() #3 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc14 = load i32, ptr @thread_local_global_with_init.2, align 4, !dbg !21
+// CHECK:STDOUT:   ret i32 %.loc14, !dbg !22
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: uwtable
-// CHECK:STDOUT: define internal void @__tls_init() #3 {
+// CHECK:STDOUT: define internal void @__tls_init() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %0 = load i8, ptr @__tls_guard, align 1
 // CHECK:STDOUT:   %guard.uninitialized = icmp eq i8 %0, 0
@@ -373,22 +376,24 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: declare ptr @llvm.invariant.start.p0(i64 immarg, ptr captures(none)) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: uwtable
-// CHECK:STDOUT: define internal void @__cxx_global_var_init() #3 section ".text.startup" {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %call = call noundef i32 @_Z4initv()
-// CHECK:STDOUT:   %0 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global_with_init)
-// CHECK:STDOUT:   store i32 %call, ptr %0, align 4, !tbaa !8
-// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: define weak_odr hidden noundef ptr @_ZTW19thread_local_global() #5 comdat {
+// CHECK:STDOUT:   %1 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global)
+// CHECK:STDOUT:   ret ptr %1
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef i32 @_Z4initv() #5
+// CHECK:STDOUT: ; Function Attrs: uwtable
+// CHECK:STDOUT: define weak_odr hidden noundef ptr @_ZTW29thread_local_global_with_init() #5 comdat {
+// CHECK:STDOUT:   call void @_ZTH29thread_local_global_with_init()
+// CHECK:STDOUT:   %1 = call align 4 ptr @llvm.threadlocal.address.p0(ptr align 4 @thread_local_global_with_init)
+// CHECK:STDOUT:   ret ptr %1
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { uwtable "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
-// CHECK:STDOUT: attributes #3 = { uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #3 = { nounwind }
 // CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #5 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #5 = { uwtable "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -397,7 +402,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -441,7 +446,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -488,7 +493,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -540,7 +545,7 @@ fn ReadStaticVarTemplateWithConstructor() -> Cpp.Y* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/import_inline.carbon b/toolchain/lower/testdata/interop/cpp/import_inline.carbon
index e97b6ab7118f..6e51e6a60704 100644
--- a/toolchain/lower/testdata/interop/cpp/import_inline.carbon
+++ b/toolchain/lower/testdata/interop/cpp/import_inline.carbon
@@ -29,33 +29,33 @@ fn Call() -> i32 {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CCall.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !16
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !16
-// CHECK:STDOUT:   store i32 0, ptr %n.var, align 4, !dbg !16
-// CHECK:STDOUT:   call void @_Z1FPi(ptr %n.var), !dbg !17
-// CHECK:STDOUT:   %.loc24 = load i32, ptr %n.var, align 4, !dbg !18
-// CHECK:STDOUT:   ret i32 %.loc24, !dbg !19
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define dso_local void @_Z1FPi(ptr noundef %p) #2 {
+// CHECK:STDOUT: define dso_local void @_Z1FPi(ptr noundef %p) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %p.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %p, ptr %p.addr, align 8, !tbaa !20
-// CHECK:STDOUT:   %0 = load ptr, ptr %p.addr, align 8, !tbaa !20
+// CHECK:STDOUT:   store ptr %p, ptr %p.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %p.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   store i32 1, ptr %0, align 4, !tbaa !8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CCall.Main() #1 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !19
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !19
+// CHECK:STDOUT:   store i32 0, ptr %n.var, align 4, !dbg !19
+// CHECK:STDOUT:   call void @_Z1FPi(ptr %n.var), !dbg !20
+// CHECK:STDOUT:   %.loc24 = load i32, ptr %n.var, align 4, !dbg !21
+// CHECK:STDOUT:   ret i32 %.loc24, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #2
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { nounwind }
+// CHECK:STDOUT: attributes #2 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -64,7 +64,7 @@ fn Call() -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -73,14 +73,14 @@ fn Call() -> i32 {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 21, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15}
-// CHECK:STDOUT: !15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !16 = !DILocation(line: 22, column: 3, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 23, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 24, column: 10, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 24, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = !{!21, !21, i64 0}
-// CHECK:STDOUT: !21 = !{!"p1 int", !22, i64 0}
-// CHECK:STDOUT: !22 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 int", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 21, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18}
+// CHECK:STDOUT: !18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !19 = !DILocation(line: 22, column: 3, scope: !15)
+// CHECK:STDOUT: !20 = !DILocation(line: 23, column: 3, scope: !15)
+// CHECK:STDOUT: !21 = !DILocation(line: 24, column: 10, scope: !15)
+// CHECK:STDOUT: !22 = !DILocation(line: 24, column: 3, scope: !15)
diff --git a/toolchain/lower/testdata/interop/cpp/method.carbon b/toolchain/lower/testdata/interop/cpp/method.carbon
index 3478fd6e49a3..eb14c6bdff91 100644
--- a/toolchain/lower/testdata/interop/cpp/method.carbon
+++ b/toolchain/lower/testdata/interop/cpp/method.carbon
@@ -83,37 +83,37 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZNK1A6by_valEv = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CUseVal.Main(ptr %a) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %by_val__carbon_thunk.call = call i32 @_ZNK1A6by_valEv.carbon_thunk(ptr %a), !dbg !19
-// CHECK:STDOUT:   ret i32 %by_val__carbon_thunk.call, !dbg !20
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef i32 @_ZNK1A6by_valEv.carbon_thunk(ptr noundef nonnull align 8 dereferenceable(12) %this) #1 {
+// CHECK:STDOUT: define dso_local noundef i32 @_ZNK1A6by_valEv.carbon_thunk(ptr noundef nonnull align 8 dereferenceable(12) %this) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   %0 = load ptr, ptr %this.addr, align 8, !tbaa !21, !nonnull !24, !align !25
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %this.addr, align 8, !tbaa !12, !nonnull !15, !align !16
 // CHECK:STDOUT:   %call = call noundef i32 @_ZNK1A6by_valEv(ptr noundef nonnull align 8 dereferenceable(12) %0)
 // CHECK:STDOUT:   ret i32 %call
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_ZNK1A6by_valEv(ptr noundef nonnull align 8 dereferenceable(12) %this) #2 comdat align 2 {
+// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_ZNK1A6by_valEv(ptr noundef nonnull align 8 dereferenceable(12) %this) #1 comdat align 2 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !21
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
 // CHECK:STDOUT:   %n = getelementptr inbounds nuw %struct.A, ptr %this1, i32 0, i32 1
-// CHECK:STDOUT:   %0 = load i32, ptr %n, align 8, !tbaa !26
+// CHECK:STDOUT:   %0 = load i32, ptr %n, align 8, !tbaa !17
 // CHECK:STDOUT:   ret i32 %0
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CUseVal.Main(ptr %a) #2 !dbg !20 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %by_val__carbon_thunk.call = call i32 @_ZNK1A6by_valEv.carbon_thunk(ptr %a), !dbg !27
+// CHECK:STDOUT:   ret i32 %by_val__carbon_thunk.call, !dbg !28
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -122,7 +122,7 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -131,23 +131,23 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "UseVal", linkageName: "_CUseVal.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !17)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15, !16}
-// CHECK:STDOUT: !15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !16 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !17 = !{!18}
-// CHECK:STDOUT: !18 = !DILocalVariable(arg: 1, scope: !12, type: !16)
-// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 10, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !{!22, !22, i64 0}
-// CHECK:STDOUT: !22 = !{!"p1 _ZTS1A", !23, i64 0}
-// CHECK:STDOUT: !23 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !24 = !{}
-// CHECK:STDOUT: !25 = !{i64 8}
-// CHECK:STDOUT: !26 = !{!27, !9, i64 8}
-// CHECK:STDOUT: !27 = !{!"_ZTS1A", !28, i64 0, !9, i64 8}
-// CHECK:STDOUT: !28 = !{!"_ZTS4Base"}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1A", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{}
+// CHECK:STDOUT: !16 = !{i64 8}
+// CHECK:STDOUT: !17 = !{!18, !9, i64 8}
+// CHECK:STDOUT: !18 = !{!"_ZTS1A", !19, i64 0, !9, i64 8}
+// CHECK:STDOUT: !19 = !{!"_ZTS4Base"}
+// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "UseVal", linkageName: "_CUseVal.Main", scope: null, file: !7, line: 6, type: !21, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !25)
+// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
+// CHECK:STDOUT: !22 = !{!23, !24}
+// CHECK:STDOUT: !23 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !24 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !25 = !{!26}
+// CHECK:STDOUT: !26 = !DILocalVariable(arg: 1, scope: !20, type: !24)
+// CHECK:STDOUT: !27 = !DILocation(line: 7, column: 10, scope: !20)
+// CHECK:STDOUT: !28 = !DILocation(line: 7, column: 3, scope: !20)
 // CHECK:STDOUT: ; ModuleID = 'call_by_ref.carbon'
 // CHECK:STDOUT: source_filename = "call_by_ref.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -186,7 +186,7 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -230,11 +230,12 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT:   ret void, !dbg !20
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN4Base5virt0Ev(ptr)
+// CHECK:STDOUT: declare void @_ZN4Base5virt0Ev(ptr noundef nonnull align 8 dereferenceable(8)) unnamed_addr #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1A5virt1Ev(ptr)
+// CHECK:STDOUT: declare void @_ZN1A5virt1Ev(ptr noundef nonnull align 8 dereferenceable(12)) unnamed_addr #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -243,7 +244,7 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -268,63 +269,63 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %struct.NeedThunk = type { i8 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCall.Main(ptr %n) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_14.3.temp = alloca i8, align 1, !dbg !18
-// CHECK:STDOUT:   %.loc8_14.3.temp = alloca i8, align 1, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_14.3.temp), !dbg !18
-// CHECK:STDOUT:   store i8 1, ptr %.loc7_14.3.temp, align 1, !dbg !18
-// CHECK:STDOUT:   call void @_ZNK9NeedThunk8ImplicitEa.carbon_thunk(ptr %n, ptr %.loc7_14.3.temp), !dbg !20
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc8_14.3.temp), !dbg !19
-// CHECK:STDOUT:   store i8 1, ptr %.loc8_14.3.temp, align 1, !dbg !19
-// CHECK:STDOUT:   call void @_ZNH9NeedThunk8ExplicitES_a.carbon_thunk(ptr %n, ptr %.loc8_14.3.temp), !dbg !21
-// CHECK:STDOUT:   ret void, !dbg !22
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZNK9NeedThunk8ImplicitEa.carbon_thunk(ptr noundef nonnull align 1 dereferenceable(1) %this, ptr noundef %c) #2 {
+// CHECK:STDOUT: define dso_local void @_ZNK9NeedThunk8ImplicitEa.carbon_thunk(ptr noundef nonnull align 1 dereferenceable(1) %this, ptr noundef %c) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %c.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !23
-// CHECK:STDOUT:   store ptr %c, ptr %c.addr, align 8, !tbaa !26
-// CHECK:STDOUT:   %0 = load ptr, ptr %this.addr, align 8, !tbaa !23, !nonnull !28
-// CHECK:STDOUT:   %1 = load ptr, ptr %c.addr, align 8, !tbaa !26
-// CHECK:STDOUT:   %2 = load i8, ptr %1, align 1, !tbaa !29
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %c, ptr %c.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %0 = load ptr, ptr %this.addr, align 8, !tbaa !12, !nonnull !17
+// CHECK:STDOUT:   %1 = load ptr, ptr %c.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %2 = load i8, ptr %1, align 1, !tbaa !18
 // CHECK:STDOUT:   call void @_ZNK9NeedThunk8ImplicitEa(ptr noundef nonnull align 1 dereferenceable(1) %0, i8 noundef signext %2)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZNK9NeedThunk8ImplicitEa(ptr noundef nonnull align 1 dereferenceable(1), i8 noundef signext) #3
+// CHECK:STDOUT: declare void @_ZNK9NeedThunk8ImplicitEa(ptr noundef nonnull align 1 dereferenceable(1), i8 noundef signext) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZNH9NeedThunk8ExplicitES_a.carbon_thunk(ptr noundef %0, ptr noundef %c) #2 {
+// CHECK:STDOUT: define dso_local void @_ZNH9NeedThunk8ExplicitES_a.carbon_thunk(ptr noundef %0, ptr noundef %c) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %c.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %struct.NeedThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !23
-// CHECK:STDOUT:   store ptr %c, ptr %c.addr, align 8, !tbaa !26
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !23
-// CHECK:STDOUT:   %2 = load ptr, ptr %c.addr, align 8, !tbaa !26
-// CHECK:STDOUT:   %3 = load i8, ptr %2, align 1, !tbaa !29
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %c, ptr %c.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %2 = load ptr, ptr %c.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %3 = load i8, ptr %2, align 1, !tbaa !18
 // CHECK:STDOUT:   call void @_ZNH9NeedThunk8ExplicitES_a(i8 noundef signext %3)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZNH9NeedThunk8ExplicitES_a(i8 noundef signext) #3
+// CHECK:STDOUT: declare void @_ZNH9NeedThunk8ExplicitES_a(i8 noundef signext) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCall.Main(ptr %n) #2 !dbg !19 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_14.3.temp = alloca i8, align 1, !dbg !25
+// CHECK:STDOUT:   %.loc8_14.3.temp = alloca i8, align 1, !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_14.3.temp), !dbg !25
+// CHECK:STDOUT:   store i8 1, ptr %.loc7_14.3.temp, align 1, !dbg !25
+// CHECK:STDOUT:   call void @_ZNK9NeedThunk8ImplicitEa.carbon_thunk(ptr %n, ptr %.loc7_14.3.temp), !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc8_14.3.temp), !dbg !26
+// CHECK:STDOUT:   store i8 1, ptr %.loc8_14.3.temp, align 1, !dbg !26
+// CHECK:STDOUT:   call void @_ZNH9NeedThunk8ExplicitES_a.carbon_thunk(ptr %n, ptr %.loc8_14.3.temp), !dbg !28
+// CHECK:STDOUT:   ret void, !dbg !29
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -333,7 +334,7 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -342,21 +343,21 @@ fn Call(n: Cpp.NeedThunk) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 7, column: 14, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 8, column: 14, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !DILocation(line: 8, column: 3, scope: !12)
-// CHECK:STDOUT: !22 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !23 = !{!24, !24, i64 0}
-// CHECK:STDOUT: !24 = !{!"p1 _ZTS9NeedThunk", !25, i64 0}
-// CHECK:STDOUT: !25 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !26 = !{!27, !27, i64 0}
-// CHECK:STDOUT: !27 = !{!"p1 omnipotent char", !25, i64 0}
-// CHECK:STDOUT: !28 = !{}
-// CHECK:STDOUT: !29 = !{!10, !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS9NeedThunk", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"p1 omnipotent char", !14, i64 0}
+// CHECK:STDOUT: !17 = !{}
+// CHECK:STDOUT: !18 = !{!10, !10, i64 0}
+// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 6, type: !20, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !23)
+// CHECK:STDOUT: !20 = !DISubroutineType(types: !21)
+// CHECK:STDOUT: !21 = !{null, !22}
+// CHECK:STDOUT: !22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !23 = !{!24}
+// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !19, type: !22)
+// CHECK:STDOUT: !25 = !DILocation(line: 7, column: 14, scope: !19)
+// CHECK:STDOUT: !26 = !DILocation(line: 8, column: 14, scope: !19)
+// CHECK:STDOUT: !27 = !DILocation(line: 7, column: 3, scope: !19)
+// CHECK:STDOUT: !28 = !DILocation(line: 8, column: 3, scope: !19)
+// CHECK:STDOUT: !29 = !DILocation(line: 6, column: 1, scope: !19)
diff --git a/toolchain/lower/testdata/interop/cpp/nullptr.carbon b/toolchain/lower/testdata/interop/cpp/nullptr.carbon
index 7c9b6565813e..58fca65fa66a 100644
--- a/toolchain/lower/testdata/interop/cpp/nullptr.carbon
+++ b/toolchain/lower/testdata/interop/cpp/nullptr.carbon
@@ -54,128 +54,128 @@ fn ConvertNullptrConstant() -> Core.Optional(i32*) {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassNullptr.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc12_18.2.temp = alloca ptr, align 8, !dbg !15
-// CHECK:STDOUT:   %.loc14_22.1.temp = alloca ptr, align 8, !dbg !16
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr poison), !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_18.2.temp), !dbg !15
-// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, ptr %.loc12_18.2.temp, align 8, !dbg !15
-// CHECK:STDOUT:   %.loc12_18.4 = load ptr, ptr %.loc12_18.2.temp, align 8, !dbg !15
-// CHECK:STDOUT:   call void @_Z7TakePtrPi(ptr %.loc12_18.4), !dbg !17
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc14_22.1.temp), !dbg !16
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !16
-// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.Copy.impl.Op.call, ptr %.loc14_22.1.temp, align 8, !dbg !16
-// CHECK:STDOUT:   call void @_Z11TakeNullptrDn.carbon_thunk(ptr %.loc14_22.1.temp), !dbg !18
-// CHECK:STDOUT:   ret void, !dbg !19
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z7TakePtrPi(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnNullptr.Main() #0 !dbg !20 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !24
-// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.Copy.impl.Op.call, !dbg !25
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnNullptrCopy.Main() #0 !dbg !26 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %a.var = alloca ptr, align 8, !dbg !27
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !27
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call.loc22 = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !28
-// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.Copy.impl.Op.call.loc22, ptr %a.var, align 8, !dbg !27
-// CHECK:STDOUT:   %.loc23 = load ptr, ptr %a.var, align 8, !dbg !29
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call.loc23 = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr %.loc23), !dbg !29
-// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.Copy.impl.Op.call.loc23, !dbg !30
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnConvertedNullptrIndirectly.Main() #0 !dbg !31 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %a.var = alloca ptr, align 8, !dbg !32
-// CHECK:STDOUT:   %.loc27_44.1.temp = alloca ptr, align 8, !dbg !33
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !32
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc27_44.1.temp), !dbg !33
-// CHECK:STDOUT:   call void @_Z13ReturnNullptrv.carbon_thunk(ptr %.loc27_44.1.temp), !dbg !33
-// CHECK:STDOUT:   %.loc27_44.2 = load ptr, ptr %.loc27_44.1.temp, align 8, !dbg !33
-// CHECK:STDOUT:   store ptr %.loc27_44.2, ptr %a.var, align 8, !dbg !32
-// CHECK:STDOUT:   %.loc28_10 = load ptr, ptr %a.var, align 8, !dbg !34
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %.loc28_10), !dbg !35
-// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !35
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnConvertedNullptrDirectly.Main() #0 !dbg !36 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc32_28.1.temp = alloca ptr, align 8, !dbg !37
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc32_28.1.temp), !dbg !37
-// CHECK:STDOUT:   call void @_Z13ReturnNullptrv.carbon_thunk(ptr %.loc32_28.1.temp), !dbg !37
-// CHECK:STDOUT:   %.loc32_28.2 = load ptr, ptr %.loc32_28.1.temp, align 8, !dbg !37
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %.loc32_28.2), !dbg !38
-// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !38
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CConvertNullptrConstant.Main() #0 !dbg !39 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr poison), !dbg !40
-// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !40
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %self) #0 !dbg !41 {
-// CHECK:STDOUT:   %1 = call ptr @_CNone.Optional.Core.7bfe1822cd6dd563(), !dbg !47
-// CHECK:STDOUT:   ret ptr %1, !dbg !48
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_CMake.NullptrT.CppCompat.Core()
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @_CNone.Optional.Core.7bfe1822cd6dd563() #0 !dbg !49 {
-// CHECK:STDOUT:   ret ptr null, !dbg !51
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11TakeNullptrDn.carbon_thunk(ptr noundef %n) #2 {
+// CHECK:STDOUT: define dso_local void @_Z11TakeNullptrDn.carbon_thunk(ptr noundef %n) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %n.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %n, ptr %n.addr, align 8, !tbaa !52
-// CHECK:STDOUT:   %0 = load ptr, ptr %n.addr, align 8, !tbaa !52
+// CHECK:STDOUT:   store ptr %n, ptr %n.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %n.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z11TakeNullptrDn(ptr null)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11TakeNullptrDn(ptr) #3
+// CHECK:STDOUT: declare void @_Z11TakeNullptrDn(ptr) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13ReturnNullptrv.carbon_thunk(ptr noundef %return) #2 {
+// CHECK:STDOUT: define dso_local void @_Z13ReturnNullptrv.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !52
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !52
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %call = call ptr @_Z13ReturnNullptrv()
-// CHECK:STDOUT:   store ptr %call, ptr %0, align 8, !tbaa !55
+// CHECK:STDOUT:   store ptr %call, ptr %0, align 8, !tbaa !15
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z13ReturnNullptrv() #3
+// CHECK:STDOUT: declare ptr @_Z13ReturnNullptrv() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassNullptr.Main() #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc12_18.2.temp = alloca ptr, align 8, !dbg !20
+// CHECK:STDOUT:   %.loc14_22.1.temp = alloca ptr, align 8, !dbg !21
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr poison), !dbg !20
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_18.2.temp), !dbg !20
+// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, ptr %.loc12_18.2.temp, align 8, !dbg !20
+// CHECK:STDOUT:   %.loc12_18.4 = load ptr, ptr %.loc12_18.2.temp, align 8, !dbg !20
+// CHECK:STDOUT:   call void @_Z7TakePtrPi(ptr %.loc12_18.4), !dbg !22
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc14_22.1.temp), !dbg !21
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !21
+// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.Copy.impl.Op.call, ptr %.loc14_22.1.temp, align 8, !dbg !21
+// CHECK:STDOUT:   call void @_Z11TakeNullptrDn.carbon_thunk(ptr %.loc14_22.1.temp), !dbg !23
+// CHECK:STDOUT:   ret void, !dbg !24
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z7TakePtrPi(ptr noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr)
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnNullptr.Main() #2 !dbg !25 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !29
+// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.Copy.impl.Op.call, !dbg !30
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnNullptrCopy.Main() #2 !dbg !31 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %a.var = alloca ptr, align 8, !dbg !32
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !32
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call.loc22 = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr poison), !dbg !33
+// CHECK:STDOUT:   store ptr %Cpp.nullptr_t.as.Copy.impl.Op.call.loc22, ptr %a.var, align 8, !dbg !32
+// CHECK:STDOUT:   %.loc23 = load ptr, ptr %a.var, align 8, !dbg !34
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.Copy.impl.Op.call.loc23 = call ptr @"_COp.NullptrT.CppCompat.Core:Copy.Core"(ptr %.loc23), !dbg !34
+// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.Copy.impl.Op.call.loc23, !dbg !35
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnConvertedNullptrIndirectly.Main() #2 !dbg !36 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %a.var = alloca ptr, align 8, !dbg !37
+// CHECK:STDOUT:   %.loc27_44.1.temp = alloca ptr, align 8, !dbg !38
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !37
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc27_44.1.temp), !dbg !38
+// CHECK:STDOUT:   call void @_Z13ReturnNullptrv.carbon_thunk(ptr %.loc27_44.1.temp), !dbg !38
+// CHECK:STDOUT:   %.loc27_44.2 = load ptr, ptr %.loc27_44.1.temp, align 8, !dbg !38
+// CHECK:STDOUT:   store ptr %.loc27_44.2, ptr %a.var, align 8, !dbg !37
+// CHECK:STDOUT:   %.loc28_10 = load ptr, ptr %a.var, align 8, !dbg !39
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %.loc28_10), !dbg !40
+// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !40
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnConvertedNullptrDirectly.Main() #2 !dbg !41 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc32_28.1.temp = alloca ptr, align 8, !dbg !42
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc32_28.1.temp), !dbg !42
+// CHECK:STDOUT:   call void @_Z13ReturnNullptrv.carbon_thunk(ptr %.loc32_28.1.temp), !dbg !42
+// CHECK:STDOUT:   %.loc32_28.2 = load ptr, ptr %.loc32_28.1.temp, align 8, !dbg !42
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %.loc32_28.2), !dbg !43
+// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !43
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CConvertNullptrConstant.Main() #2 !dbg !44 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr poison), !dbg !45
+// CHECK:STDOUT:   ret ptr %Cpp.nullptr_t.as.ImplicitAs.impl.Convert.call, !dbg !45
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4"(ptr %self) #2 !dbg !46 {
+// CHECK:STDOUT:   %1 = call ptr @_CNone.Optional.Core.7bfe1822cd6dd563(), !dbg !52
+// CHECK:STDOUT:   ret ptr %1, !dbg !53
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare ptr @_CMake.NullptrT.CppCompat.Core()
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @_CNone.Optional.Core.7bfe1822cd6dd563() #2 !dbg !54 {
+// CHECK:STDOUT:   ret ptr null, !dbg !56
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @"_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4", { 3, 2, 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 5, 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -184,7 +184,7 @@ fn ConvertNullptrConstant() -> Core.Optional(i32*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -193,48 +193,48 @@ fn ConvertNullptrConstant() -> Core.Optional(i32*) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassNullptr", linkageName: "_CPassNullptr.Main", scope: null, file: !7, line: 11, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 12, column: 15, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 14, column: 19, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 12, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 14, column: 3, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 11, column: 1, scope: !12)
-// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "ReturnNullptr", linkageName: "_CReturnNullptr.Main", scope: null, file: !7, line: 17, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
-// CHECK:STDOUT: !22 = !{!23}
-// CHECK:STDOUT: !23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !24 = !DILocation(line: 18, column: 10, scope: !20)
-// CHECK:STDOUT: !25 = !DILocation(line: 18, column: 3, scope: !20)
-// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "ReturnNullptrCopy", linkageName: "_CReturnNullptrCopy.Main", scope: null, file: !7, line: 21, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !27 = !DILocation(line: 22, column: 3, scope: !26)
-// CHECK:STDOUT: !28 = !DILocation(line: 22, column: 26, scope: !26)
-// CHECK:STDOUT: !29 = !DILocation(line: 23, column: 10, scope: !26)
-// CHECK:STDOUT: !30 = !DILocation(line: 23, column: 3, scope: !26)
-// CHECK:STDOUT: !31 = distinct !DISubprogram(name: "ReturnConvertedNullptrIndirectly", linkageName: "_CReturnConvertedNullptrIndirectly.Main", scope: null, file: !7, line: 26, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !32 = !DILocation(line: 27, column: 3, scope: !31)
-// CHECK:STDOUT: !33 = !DILocation(line: 27, column: 26, scope: !31)
-// CHECK:STDOUT: !34 = !DILocation(line: 28, column: 10, scope: !31)
-// CHECK:STDOUT: !35 = !DILocation(line: 28, column: 3, scope: !31)
-// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "ReturnConvertedNullptrDirectly", linkageName: "_CReturnConvertedNullptrDirectly.Main", scope: null, file: !7, line: 31, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !37 = !DILocation(line: 32, column: 10, scope: !36)
-// CHECK:STDOUT: !38 = !DILocation(line: 32, column: 3, scope: !36)
-// CHECK:STDOUT: !39 = distinct !DISubprogram(name: "ConvertNullptrConstant", linkageName: "_CConvertNullptrConstant.Main", scope: null, file: !7, line: 35, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !40 = !DILocation(line: 36, column: 3, scope: !39)
-// CHECK:STDOUT: !41 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4", scope: null, file: !42, line: 46, type: !43, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !45)
-// CHECK:STDOUT: !42 = !DIFile(filename: "{{.*}}/prelude/types/cpp/nullptr.carbon", directory: "")
-// CHECK:STDOUT: !43 = !DISubroutineType(types: !44)
-// CHECK:STDOUT: !44 = !{!23, !23}
-// CHECK:STDOUT: !45 = !{!46}
-// CHECK:STDOUT: !46 = !DILocalVariable(arg: 1, scope: !41, type: !23)
-// CHECK:STDOUT: !47 = !DILocation(line: 47, column: 14, scope: !41)
-// CHECK:STDOUT: !48 = !DILocation(line: 47, column: 7, scope: !41)
-// CHECK:STDOUT: !49 = distinct !DISubprogram(name: "None", linkageName: "_CNone.Optional.Core.7bfe1822cd6dd563", scope: null, file: !50, line: 26, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !50 = !DIFile(filename: "{{.*}}/prelude/types/optional.carbon", directory: "")
-// CHECK:STDOUT: !51 = !DILocation(line: 27, column: 5, scope: !49)
-// CHECK:STDOUT: !52 = !{!53, !53, i64 0}
-// CHECK:STDOUT: !53 = !{!"p1 std::nullptr_t", !54, i64 0}
-// CHECK:STDOUT: !54 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !55 = !{!56, !56, i64 0}
-// CHECK:STDOUT: !56 = !{!"std::nullptr_t", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 std::nullptr_t", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"std::nullptr_t", !10, i64 0}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "PassNullptr", linkageName: "_CPassNullptr.Main", scope: null, file: !7, line: 11, type: !18, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{null}
+// CHECK:STDOUT: !20 = !DILocation(line: 12, column: 15, scope: !17)
+// CHECK:STDOUT: !21 = !DILocation(line: 14, column: 19, scope: !17)
+// CHECK:STDOUT: !22 = !DILocation(line: 12, column: 3, scope: !17)
+// CHECK:STDOUT: !23 = !DILocation(line: 14, column: 3, scope: !17)
+// CHECK:STDOUT: !24 = !DILocation(line: 11, column: 1, scope: !17)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "ReturnNullptr", linkageName: "_CReturnNullptr.Main", scope: null, file: !7, line: 17, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
+// CHECK:STDOUT: !27 = !{!28}
+// CHECK:STDOUT: !28 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !29 = !DILocation(line: 18, column: 10, scope: !25)
+// CHECK:STDOUT: !30 = !DILocation(line: 18, column: 3, scope: !25)
+// CHECK:STDOUT: !31 = distinct !DISubprogram(name: "ReturnNullptrCopy", linkageName: "_CReturnNullptrCopy.Main", scope: null, file: !7, line: 21, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !32 = !DILocation(line: 22, column: 3, scope: !31)
+// CHECK:STDOUT: !33 = !DILocation(line: 22, column: 26, scope: !31)
+// CHECK:STDOUT: !34 = !DILocation(line: 23, column: 10, scope: !31)
+// CHECK:STDOUT: !35 = !DILocation(line: 23, column: 3, scope: !31)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "ReturnConvertedNullptrIndirectly", linkageName: "_CReturnConvertedNullptrIndirectly.Main", scope: null, file: !7, line: 26, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !37 = !DILocation(line: 27, column: 3, scope: !36)
+// CHECK:STDOUT: !38 = !DILocation(line: 27, column: 26, scope: !36)
+// CHECK:STDOUT: !39 = !DILocation(line: 28, column: 10, scope: !36)
+// CHECK:STDOUT: !40 = !DILocation(line: 28, column: 3, scope: !36)
+// CHECK:STDOUT: !41 = distinct !DISubprogram(name: "ReturnConvertedNullptrDirectly", linkageName: "_CReturnConvertedNullptrDirectly.Main", scope: null, file: !7, line: 31, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !42 = !DILocation(line: 32, column: 10, scope: !41)
+// CHECK:STDOUT: !43 = !DILocation(line: 32, column: 3, scope: !41)
+// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "ConvertNullptrConstant", linkageName: "_CConvertNullptrConstant.Main", scope: null, file: !7, line: 35, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !45 = !DILocation(line: 36, column: 3, scope: !44)
+// CHECK:STDOUT: !46 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.NullptrT.CppCompat.Core:ImplicitAs.95db8d3a03540861.Core.b88d1103f417c6d4", scope: null, file: !47, line: 46, type: !48, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !50)
+// CHECK:STDOUT: !47 = !DIFile(filename: "{{.*}}/prelude/types/cpp/nullptr.carbon", directory: "")
+// CHECK:STDOUT: !48 = !DISubroutineType(types: !49)
+// CHECK:STDOUT: !49 = !{!28, !28}
+// CHECK:STDOUT: !50 = !{!51}
+// CHECK:STDOUT: !51 = !DILocalVariable(arg: 1, scope: !46, type: !28)
+// CHECK:STDOUT: !52 = !DILocation(line: 47, column: 14, scope: !46)
+// CHECK:STDOUT: !53 = !DILocation(line: 47, column: 7, scope: !46)
+// CHECK:STDOUT: !54 = distinct !DISubprogram(name: "None", linkageName: "_CNone.Optional.Core.7bfe1822cd6dd563", scope: null, file: !55, line: 26, type: !26, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !55 = !DIFile(filename: "{{.*}}/prelude/types/optional.carbon", directory: "")
+// CHECK:STDOUT: !56 = !DILocation(line: 27, column: 5, scope: !54)
diff --git a/toolchain/lower/testdata/interop/cpp/parameters.carbon b/toolchain/lower/testdata/interop/cpp/parameters.carbon
index 1329e10483aa..66aeff526286 100644
--- a/toolchain/lower/testdata/interop/cpp/parameters.carbon
+++ b/toolchain/lower/testdata/interop/cpp/parameters.carbon
@@ -115,122 +115,122 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @_Cc.Main = global i16 0
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CMyF.Main() #0 !dbg !12 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z11pass_signedasil.carbon_thunk(ptr noundef %0, ptr noundef %1, i32 noundef %2, i64 noundef %3) #0 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_19.3.temp = alloca i8, align 1, !dbg !15
-// CHECK:STDOUT:   %.loc7_22.3.temp = alloca i16, align 2, !dbg !16
-// CHECK:STDOUT:   %.loc9_21.3.temp = alloca i8, align 1, !dbg !17
-// CHECK:STDOUT:   %.loc9_24.3.temp = alloca i16, align 2, !dbg !18
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_19.3.temp), !dbg !15
-// CHECK:STDOUT:   store i8 1, ptr %.loc7_19.3.temp, align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_22.3.temp), !dbg !16
-// CHECK:STDOUT:   store i16 2, ptr %.loc7_22.3.temp, align 2, !dbg !16
-// CHECK:STDOUT:   call void @_Z11pass_signedasil.carbon_thunk(ptr %.loc7_19.3.temp, ptr %.loc7_22.3.temp, i32 3, i64 4), !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_21.3.temp), !dbg !17
-// CHECK:STDOUT:   store i8 1, ptr %.loc9_21.3.temp, align 1, !dbg !17
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_24.3.temp), !dbg !18
-// CHECK:STDOUT:   store i16 2, ptr %.loc9_24.3.temp, align 2, !dbg !18
-// CHECK:STDOUT:   call void @_Z13pass_unsignedhtjm.carbon_thunk(ptr %.loc9_21.3.temp, ptr %.loc9_24.3.temp, i32 3, i64 4), !dbg !20
-// CHECK:STDOUT:   ret void, !dbg !21
+// CHECK:STDOUT:   %.addr = alloca ptr, align 8
+// CHECK:STDOUT:   %.addr1 = alloca ptr, align 8
+// CHECK:STDOUT:   %.addr2 = alloca i32, align 4
+// CHECK:STDOUT:   %.addr3 = alloca i64, align 8
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !15
+// CHECK:STDOUT:   store i32 %2, ptr %.addr2, align 4, !tbaa !8
+// CHECK:STDOUT:   store i64 %3, ptr %.addr3, align 8, !tbaa !17
+// CHECK:STDOUT:   %4 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %5 = load i8, ptr %4, align 1, !tbaa !19
+// CHECK:STDOUT:   %6 = load ptr, ptr %.addr1, align 8, !tbaa !15
+// CHECK:STDOUT:   %7 = load i16, ptr %6, align 2, !tbaa !20
+// CHECK:STDOUT:   %8 = load i32, ptr %.addr2, align 4, !tbaa !8
+// CHECK:STDOUT:   %9 = load i64, ptr %.addr3, align 8, !tbaa !17
+// CHECK:STDOUT:   call void @_Z11pass_signedasil(i8 noundef signext %5, i16 noundef signext %7, i32 noundef %8, i64 noundef %9)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z11pass_signedasil(i8 noundef signext, i16 noundef signext, i32 noundef, i64 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z13pass_unsignedhtjm.carbon_thunk(ptr noundef %0, ptr noundef %1, i32 noundef %2, i64 noundef %3) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.addr = alloca ptr, align 8
+// CHECK:STDOUT:   %.addr1 = alloca ptr, align 8
+// CHECK:STDOUT:   %.addr2 = alloca i32, align 4
+// CHECK:STDOUT:   %.addr3 = alloca i64, align 8
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !15
+// CHECK:STDOUT:   store i32 %2, ptr %.addr2, align 4, !tbaa !8
+// CHECK:STDOUT:   store i64 %3, ptr %.addr3, align 8, !tbaa !17
+// CHECK:STDOUT:   %4 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %5 = load i8, ptr %4, align 1, !tbaa !19
+// CHECK:STDOUT:   %6 = load ptr, ptr %.addr1, align 8, !tbaa !15
+// CHECK:STDOUT:   %7 = load i16, ptr %6, align 2, !tbaa !20
+// CHECK:STDOUT:   %8 = load i32, ptr %.addr2, align 4, !tbaa !8
+// CHECK:STDOUT:   %9 = load i64, ptr %.addr3, align 8, !tbaa !17
+// CHECK:STDOUT:   call void @_Z13pass_unsignedhtjm(i8 noundef zeroext %5, i16 noundef zeroext %7, i32 noundef %8, i64 noundef %9)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z13pass_unsignedhtjm(i8 noundef zeroext, i16 noundef zeroext, i32 noundef, i64 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z10pass_shorts.carbon_thunk(ptr noundef %0) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !20
+// CHECK:STDOUT:   call void @_Z10pass_shorts(i16 noundef signext %2)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z10pass_shorts(i16 noundef signext) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CMyF.Main() #2 !dbg !22 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc7_19.3.temp = alloca i8, align 1, !dbg !25
+// CHECK:STDOUT:   %.loc7_22.3.temp = alloca i16, align 2, !dbg !26
+// CHECK:STDOUT:   %.loc9_21.3.temp = alloca i8, align 1, !dbg !27
+// CHECK:STDOUT:   %.loc9_24.3.temp = alloca i16, align 2, !dbg !28
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_19.3.temp), !dbg !25
+// CHECK:STDOUT:   store i8 1, ptr %.loc7_19.3.temp, align 1, !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_22.3.temp), !dbg !26
+// CHECK:STDOUT:   store i16 2, ptr %.loc7_22.3.temp, align 2, !dbg !26
+// CHECK:STDOUT:   call void @_Z11pass_signedasil.carbon_thunk(ptr %.loc7_19.3.temp, ptr %.loc7_22.3.temp, i32 3, i64 4), !dbg !29
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_21.3.temp), !dbg !27
+// CHECK:STDOUT:   store i8 1, ptr %.loc9_21.3.temp, align 1, !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_24.3.temp), !dbg !28
+// CHECK:STDOUT:   store i16 2, ptr %.loc9_24.3.temp, align 2, !dbg !28
+// CHECK:STDOUT:   call void @_Z13pass_unsignedhtjm.carbon_thunk(ptr %.loc9_21.3.temp, ptr %.loc9_24.3.temp, i32 3, i64 4), !dbg !30
+// CHECK:STDOUT:   ret void, !dbg !31
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare i16 @_CMakeShort.Main()
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassShort.Main(i16 %a, ptr %b) #0 !dbg !22 {
+// CHECK:STDOUT: define void @_CPassShort.Main(i16 %a, ptr %b) #2 !dbg !32 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc17_18.1.temp = alloca i16, align 2, !dbg !30
-// CHECK:STDOUT:   %.loc18_18.3.temp = alloca i16, align 2, !dbg !31
-// CHECK:STDOUT:   %.loc19_18.2.temp = alloca i16, align 2, !dbg !32
-// CHECK:STDOUT:   %.loc20_28.3.temp = alloca i16, align 2, !dbg !33
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_18.1.temp), !dbg !30
-// CHECK:STDOUT:   store i16 %a, ptr %.loc17_18.1.temp, align 2, !dbg !30
-// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc17_18.1.temp), !dbg !34
-// CHECK:STDOUT:   %.loc18_18.2 = load i16, ptr %b, align 2, !dbg !31
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc18_18.3.temp), !dbg !31
-// CHECK:STDOUT:   store i16 %.loc18_18.2, ptr %.loc18_18.3.temp, align 2, !dbg !31
-// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc18_18.3.temp), !dbg !35
-// CHECK:STDOUT:   %.loc19_18.1 = load i16, ptr @_Cc.Main, align 2, !dbg !32
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !32
-// CHECK:STDOUT:   store i16 %.loc19_18.1, ptr %.loc19_18.2.temp, align 2, !dbg !32
-// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !36
-// CHECK:STDOUT:   %MakeShort.call = call i16 @_CMakeShort.Main(), !dbg !33
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_28.3.temp), !dbg !33
-// CHECK:STDOUT:   store i16 %MakeShort.call, ptr %.loc20_28.3.temp, align 2, !dbg !33
-// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc20_28.3.temp), !dbg !37
-// CHECK:STDOUT:   ret void, !dbg !38
+// CHECK:STDOUT:   %.loc17_18.1.temp = alloca i16, align 2, !dbg !40
+// CHECK:STDOUT:   %.loc18_18.3.temp = alloca i16, align 2, !dbg !41
+// CHECK:STDOUT:   %.loc19_18.2.temp = alloca i16, align 2, !dbg !42
+// CHECK:STDOUT:   %.loc20_28.3.temp = alloca i16, align 2, !dbg !43
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_18.1.temp), !dbg !40
+// CHECK:STDOUT:   store i16 %a, ptr %.loc17_18.1.temp, align 2, !dbg !40
+// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc17_18.1.temp), !dbg !44
+// CHECK:STDOUT:   %.loc18_18.2 = load i16, ptr %b, align 2, !dbg !41
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc18_18.3.temp), !dbg !41
+// CHECK:STDOUT:   store i16 %.loc18_18.2, ptr %.loc18_18.3.temp, align 2, !dbg !41
+// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc18_18.3.temp), !dbg !45
+// CHECK:STDOUT:   %.loc19_18.1 = load i16, ptr @_Cc.Main, align 2, !dbg !42
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !42
+// CHECK:STDOUT:   store i16 %.loc19_18.1, ptr %.loc19_18.2.temp, align 2, !dbg !42
+// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !46
+// CHECK:STDOUT:   %MakeShort.call = call i16 @_CMakeShort.Main(), !dbg !43
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_28.3.temp), !dbg !43
+// CHECK:STDOUT:   store i16 %MakeShort.call, ptr %.loc20_28.3.temp, align 2, !dbg !43
+// CHECK:STDOUT:   call void @_Z10pass_shorts.carbon_thunk(ptr %.loc20_28.3.temp), !dbg !47
+// CHECK:STDOUT:   ret void, !dbg !48
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11pass_signedasil.carbon_thunk(ptr noundef %0, ptr noundef %1, i32 noundef %2, i64 noundef %3) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   %.addr1 = alloca ptr, align 8
-// CHECK:STDOUT:   %.addr2 = alloca i32, align 4
-// CHECK:STDOUT:   %.addr3 = alloca i64, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !39
-// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !42
-// CHECK:STDOUT:   store i32 %2, ptr %.addr2, align 4, !tbaa !8
-// CHECK:STDOUT:   store i64 %3, ptr %.addr3, align 8, !tbaa !44
-// CHECK:STDOUT:   %4 = load ptr, ptr %.addr, align 8, !tbaa !39
-// CHECK:STDOUT:   %5 = load i8, ptr %4, align 1, !tbaa !46
-// CHECK:STDOUT:   %6 = load ptr, ptr %.addr1, align 8, !tbaa !42
-// CHECK:STDOUT:   %7 = load i16, ptr %6, align 2, !tbaa !47
-// CHECK:STDOUT:   %8 = load i32, ptr %.addr2, align 4, !tbaa !8
-// CHECK:STDOUT:   %9 = load i64, ptr %.addr3, align 8, !tbaa !44
-// CHECK:STDOUT:   call void @_Z11pass_signedasil(i8 noundef signext %5, i16 noundef signext %7, i32 noundef %8, i64 noundef %9)
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11pass_signedasil(i8 noundef signext, i16 noundef signext, i32 noundef, i64 noundef) #3
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13pass_unsignedhtjm.carbon_thunk(ptr noundef %0, ptr noundef %1, i32 noundef %2, i64 noundef %3) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   %.addr1 = alloca ptr, align 8
-// CHECK:STDOUT:   %.addr2 = alloca i32, align 4
-// CHECK:STDOUT:   %.addr3 = alloca i64, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !39
-// CHECK:STDOUT:   store ptr %1, ptr %.addr1, align 8, !tbaa !42
-// CHECK:STDOUT:   store i32 %2, ptr %.addr2, align 4, !tbaa !8
-// CHECK:STDOUT:   store i64 %3, ptr %.addr3, align 8, !tbaa !44
-// CHECK:STDOUT:   %4 = load ptr, ptr %.addr, align 8, !tbaa !39
-// CHECK:STDOUT:   %5 = load i8, ptr %4, align 1, !tbaa !46
-// CHECK:STDOUT:   %6 = load ptr, ptr %.addr1, align 8, !tbaa !42
-// CHECK:STDOUT:   %7 = load i16, ptr %6, align 2, !tbaa !47
-// CHECK:STDOUT:   %8 = load i32, ptr %.addr2, align 4, !tbaa !8
-// CHECK:STDOUT:   %9 = load i64, ptr %.addr3, align 8, !tbaa !44
-// CHECK:STDOUT:   call void @_Z13pass_unsignedhtjm(i8 noundef zeroext %5, i16 noundef zeroext %7, i32 noundef %8, i64 noundef %9)
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13pass_unsignedhtjm(i8 noundef zeroext, i16 noundef zeroext, i32 noundef, i64 noundef) #3
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z10pass_shorts.carbon_thunk(ptr noundef %0) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !42
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !42
-// CHECK:STDOUT:   %2 = load i16, ptr %1, align 2, !tbaa !47
-// CHECK:STDOUT:   call void @_Z10pass_shorts(i16 noundef signext %2)
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z10pass_shorts(i16 noundef signext) #3
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 7, 6, 5, 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -239,7 +239,7 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -248,43 +248,43 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "MyF", linkageName: "_CMyF.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 19, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 7, column: 22, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 9, column: 21, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 9, column: 24, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 9, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "PassShort", linkageName: "_CPassShort.Main", scope: null, file: !7, line: 16, type: !23, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !27)
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 omnipotent char", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"p1 short", !14, i64 0}
+// CHECK:STDOUT: !17 = !{!18, !18, i64 0}
+// CHECK:STDOUT: !18 = !{!"long", !10, i64 0}
+// CHECK:STDOUT: !19 = !{!10, !10, i64 0}
+// CHECK:STDOUT: !20 = !{!21, !21, i64 0}
+// CHECK:STDOUT: !21 = !{!"short", !10, i64 0}
+// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "MyF", linkageName: "_CMyF.Main", scope: null, file: !7, line: 6, type: !23, spFlags: DISPFlagDefinition, unit: !6)
 // CHECK:STDOUT: !23 = !DISubroutineType(types: !24)
-// CHECK:STDOUT: !24 = !{null, !25, !26}
-// CHECK:STDOUT: !25 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !26 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !27 = !{!28, !29}
-// CHECK:STDOUT: !28 = !DILocalVariable(arg: 1, scope: !22, type: !25)
-// CHECK:STDOUT: !29 = !DILocalVariable(arg: 2, scope: !22, type: !26)
-// CHECK:STDOUT: !30 = !DILocation(line: 17, column: 18, scope: !22)
-// CHECK:STDOUT: !31 = !DILocation(line: 18, column: 18, scope: !22)
-// CHECK:STDOUT: !32 = !DILocation(line: 19, column: 18, scope: !22)
-// CHECK:STDOUT: !33 = !DILocation(line: 20, column: 18, scope: !22)
-// CHECK:STDOUT: !34 = !DILocation(line: 17, column: 3, scope: !22)
-// CHECK:STDOUT: !35 = !DILocation(line: 18, column: 3, scope: !22)
-// CHECK:STDOUT: !36 = !DILocation(line: 19, column: 3, scope: !22)
-// CHECK:STDOUT: !37 = !DILocation(line: 20, column: 3, scope: !22)
-// CHECK:STDOUT: !38 = !DILocation(line: 16, column: 1, scope: !22)
-// CHECK:STDOUT: !39 = !{!40, !40, i64 0}
-// CHECK:STDOUT: !40 = !{!"p1 omnipotent char", !41, i64 0}
-// CHECK:STDOUT: !41 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !42 = !{!43, !43, i64 0}
-// CHECK:STDOUT: !43 = !{!"p1 short", !41, i64 0}
-// CHECK:STDOUT: !44 = !{!45, !45, i64 0}
-// CHECK:STDOUT: !45 = !{!"long", !10, i64 0}
-// CHECK:STDOUT: !46 = !{!10, !10, i64 0}
-// CHECK:STDOUT: !47 = !{!48, !48, i64 0}
-// CHECK:STDOUT: !48 = !{!"short", !10, i64 0}
+// CHECK:STDOUT: !24 = !{null}
+// CHECK:STDOUT: !25 = !DILocation(line: 7, column: 19, scope: !22)
+// CHECK:STDOUT: !26 = !DILocation(line: 7, column: 22, scope: !22)
+// CHECK:STDOUT: !27 = !DILocation(line: 9, column: 21, scope: !22)
+// CHECK:STDOUT: !28 = !DILocation(line: 9, column: 24, scope: !22)
+// CHECK:STDOUT: !29 = !DILocation(line: 7, column: 3, scope: !22)
+// CHECK:STDOUT: !30 = !DILocation(line: 9, column: 3, scope: !22)
+// CHECK:STDOUT: !31 = !DILocation(line: 6, column: 1, scope: !22)
+// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "PassShort", linkageName: "_CPassShort.Main", scope: null, file: !7, line: 16, type: !33, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !37)
+// CHECK:STDOUT: !33 = !DISubroutineType(types: !34)
+// CHECK:STDOUT: !34 = !{null, !35, !36}
+// CHECK:STDOUT: !35 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !36 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !37 = !{!38, !39}
+// CHECK:STDOUT: !38 = !DILocalVariable(arg: 1, scope: !32, type: !35)
+// CHECK:STDOUT: !39 = !DILocalVariable(arg: 2, scope: !32, type: !36)
+// CHECK:STDOUT: !40 = !DILocation(line: 17, column: 18, scope: !32)
+// CHECK:STDOUT: !41 = !DILocation(line: 18, column: 18, scope: !32)
+// CHECK:STDOUT: !42 = !DILocation(line: 19, column: 18, scope: !32)
+// CHECK:STDOUT: !43 = !DILocation(line: 20, column: 18, scope: !32)
+// CHECK:STDOUT: !44 = !DILocation(line: 17, column: 3, scope: !32)
+// CHECK:STDOUT: !45 = !DILocation(line: 18, column: 3, scope: !32)
+// CHECK:STDOUT: !46 = !DILocation(line: 19, column: 3, scope: !32)
+// CHECK:STDOUT: !47 = !DILocation(line: 20, column: 3, scope: !32)
+// CHECK:STDOUT: !48 = !DILocation(line: 16, column: 1, scope: !32)
 // CHECK:STDOUT: ; ModuleID = 'import_struct.carbon'
 // CHECK:STDOUT: source_filename = "import_struct.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -292,33 +292,15 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %struct.X = type { i32, i32, i32 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CTest.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %x.var = alloca [12 x i8], align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %x.var), !dbg !15
-// CHECK:STDOUT:   %.loc8_4.a = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 0, !dbg !16
-// CHECK:STDOUT:   store i32 1, ptr %.loc8_4.a, align 4, !dbg !16
-// CHECK:STDOUT:   %.loc9_4.b = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 4, !dbg !17
-// CHECK:STDOUT:   store i32 2, ptr %.loc9_4.b, align 4, !dbg !17
-// CHECK:STDOUT:   %.loc10_4.c = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 8, !dbg !18
-// CHECK:STDOUT:   store i32 3, ptr %.loc10_4.c, align 4, !dbg !18
-// CHECK:STDOUT:   call void @_Z11pass_struct1X.carbon_thunk(ptr %x.var), !dbg !19
-// CHECK:STDOUT:   ret void, !dbg !20
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11pass_struct1X.carbon_thunk(ptr noundef %0) #2 {
+// CHECK:STDOUT: define dso_local void @_Z11pass_struct1X.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %struct.X, align 4
 // CHECK:STDOUT:   %agg.tmp.coerce = alloca { i64, i32 }, align 4
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !21
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %agg.tmp, ptr align 4 %1, i64 12, i1 false), !tbaa.struct !24
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %agg.tmp, ptr align 4 %1, i64 12, i1 false), !tbaa.struct !15
 // CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %agg.tmp.coerce, ptr align 4 %agg.tmp, i64 12, i1 false)
 // CHECK:STDOUT:   %2 = getelementptr inbounds nuw { i64, i32 }, ptr %agg.tmp.coerce, i32 0, i32 0
 // CHECK:STDOUT:   %3 = load i64, ptr %2, align 4
@@ -328,19 +310,37 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #3
+// CHECK:STDOUT: declare void @_Z11pass_struct1X(i64, i32) #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11pass_struct1X(i64, i32) #4
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #2
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CTest.Main() #3 !dbg !16 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %x.var = alloca [12 x i8], align 1, !dbg !19
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %x.var), !dbg !19
+// CHECK:STDOUT:   %.loc8_4.a = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 0, !dbg !20
+// CHECK:STDOUT:   store i32 1, ptr %.loc8_4.a, align 4, !dbg !20
+// CHECK:STDOUT:   %.loc9_4.b = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 4, !dbg !21
+// CHECK:STDOUT:   store i32 2, ptr %.loc9_4.b, align 4, !dbg !21
+// CHECK:STDOUT:   %.loc10_4.c = getelementptr inbounds nuw [12 x i8], ptr %x.var, i32 0, i32 8, !dbg !22
+// CHECK:STDOUT:   store i32 3, ptr %.loc10_4.c, align 4, !dbg !22
+// CHECK:STDOUT:   call void @_Z11pass_struct1X.carbon_thunk(ptr %x.var), !dbg !23
+// CHECK:STDOUT:   ret void, !dbg !24
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -349,7 +349,7 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -358,19 +358,19 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Test", linkageName: "_CTest.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 8, column: 3, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 9, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 10, column: 3, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 11, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !21 = !{!22, !22, i64 0}
-// CHECK:STDOUT: !22 = !{!"p1 _ZTS1X", !23, i64 0}
-// CHECK:STDOUT: !23 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !24 = !{i64 0, i64 4, !8, i64 4, i64 4, !8, i64 8, i64 4, !8}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1X", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{i64 0, i64 4, !8, i64 4, i64 4, !8, i64 8, i64 4, !8}
+// CHECK:STDOUT: !16 = distinct !DISubprogram(name: "Test", linkageName: "_CTest.Main", scope: null, file: !7, line: 6, type: !17, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !17 = !DISubroutineType(types: !18)
+// CHECK:STDOUT: !18 = !{null}
+// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 3, scope: !16)
+// CHECK:STDOUT: !20 = !DILocation(line: 8, column: 3, scope: !16)
+// CHECK:STDOUT: !21 = !DILocation(line: 9, column: 3, scope: !16)
+// CHECK:STDOUT: !22 = !DILocation(line: 10, column: 3, scope: !16)
+// CHECK:STDOUT: !23 = !DILocation(line: 11, column: 3, scope: !16)
+// CHECK:STDOUT: !24 = !DILocation(line: 6, column: 1, scope: !16)
 // CHECK:STDOUT: ; ModuleID = 'import_class_with_nontrivial_copy.carbon'
 // CHECK:STDOUT: source_filename = "import_class_with_nontrivial_copy.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -378,66 +378,66 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %class.Y = type { i32, i32, i32 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassRefExpr.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %y.var = alloca [12 x i8], align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %y.var), !dbg !15
-// CHECK:STDOUT:   %.loc8_4.a = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 0, !dbg !16
-// CHECK:STDOUT:   store i32 1, ptr %.loc8_4.a, align 4, !dbg !16
-// CHECK:STDOUT:   %.loc9_4.b = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 4, !dbg !17
-// CHECK:STDOUT:   store i32 2, ptr %.loc9_4.b, align 4, !dbg !17
-// CHECK:STDOUT:   %.loc10_4.c = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 8, !dbg !18
-// CHECK:STDOUT:   store i32 3, ptr %.loc10_4.c, align 4, !dbg !18
-// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %y.var), !dbg !19
-// CHECK:STDOUT:   ret void, !dbg !20
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_CMake.Main(ptr sret([12 x i8]))
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassInitExpr.Main() #0 !dbg !21 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc17_24.1.temp = alloca [12 x i8], align 1, !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_24.1.temp), !dbg !22
-// CHECK:STDOUT:   call void @_CMake.Main(ptr %.loc17_24.1.temp), !dbg !22
-// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %.loc17_24.1.temp), !dbg !23
-// CHECK:STDOUT:   ret void, !dbg !24
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassValueExpr.Main(ptr %y) #0 !dbg !25 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %y), !dbg !31
-// CHECK:STDOUT:   ret void, !dbg !32
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11pass_struct1Y.carbon_thunk(ptr noundef %0) #2 {
+// CHECK:STDOUT: define dso_local void @_Z11pass_struct1Y.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.Y, align 4
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !33
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !33
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_ZN1YC1ERKS_(ptr noundef nonnull align 4 dereferenceable(12) %agg.tmp, ptr noundef nonnull align 4 dereferenceable(12) %1)
 // CHECK:STDOUT:   call void @_Z11pass_struct1Y(ptr dead_on_return noundef %agg.tmp)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1YC1ERKS_(ptr noundef nonnull align 4 dereferenceable(12), ptr noundef nonnull align 4 dereferenceable(12)) unnamed_addr #3
+// CHECK:STDOUT: declare void @_Z11pass_struct1Y(ptr dead_on_return noundef) #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11pass_struct1Y(ptr dead_on_return noundef) #3
+// CHECK:STDOUT: declare void @_ZN1YC1ERKS_(ptr noundef nonnull align 4 dereferenceable(12), ptr noundef nonnull align 4 dereferenceable(12)) unnamed_addr #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassRefExpr.Main() #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %y.var = alloca [12 x i8], align 1, !dbg !18
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %y.var), !dbg !18
+// CHECK:STDOUT:   %.loc8_4.a = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 0, !dbg !19
+// CHECK:STDOUT:   store i32 1, ptr %.loc8_4.a, align 4, !dbg !19
+// CHECK:STDOUT:   %.loc9_4.b = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 4, !dbg !20
+// CHECK:STDOUT:   store i32 2, ptr %.loc9_4.b, align 4, !dbg !20
+// CHECK:STDOUT:   %.loc10_4.c = getelementptr inbounds nuw [12 x i8], ptr %y.var, i32 0, i32 8, !dbg !21
+// CHECK:STDOUT:   store i32 3, ptr %.loc10_4.c, align 4, !dbg !21
+// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %y.var), !dbg !22
+// CHECK:STDOUT:   ret void, !dbg !23
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_CMake.Main(ptr sret([12 x i8]))
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassInitExpr.Main() #2 !dbg !24 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc17_24.1.temp = alloca [12 x i8], align 1, !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc17_24.1.temp), !dbg !25
+// CHECK:STDOUT:   call void @_CMake.Main(ptr %.loc17_24.1.temp), !dbg !25
+// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %.loc17_24.1.temp), !dbg !26
+// CHECK:STDOUT:   ret void, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassValueExpr.Main(ptr %y) #2 !dbg !28 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z11pass_struct1Y.carbon_thunk(ptr %y), !dbg !34
+// CHECK:STDOUT:   ret void, !dbg !35
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -446,7 +446,7 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -455,27 +455,27 @@ fn PassValueExpr(y: Cpp.Y) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassRefExpr", linkageName: "_CPassRefExpr.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 8, column: 3, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 9, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 10, column: 3, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 11, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "PassInitExpr", linkageName: "_CPassInitExpr.Main", scope: null, file: !7, line: 16, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !22 = !DILocation(line: 17, column: 19, scope: !21)
-// CHECK:STDOUT: !23 = !DILocation(line: 17, column: 3, scope: !21)
-// CHECK:STDOUT: !24 = !DILocation(line: 16, column: 1, scope: !21)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "PassValueExpr", linkageName: "_CPassValueExpr.Main", scope: null, file: !7, line: 20, type: !26, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !29)
-// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
-// CHECK:STDOUT: !27 = !{null, !28}
-// CHECK:STDOUT: !28 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !29 = !{!30}
-// CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !28)
-// CHECK:STDOUT: !31 = !DILocation(line: 21, column: 3, scope: !25)
-// CHECK:STDOUT: !32 = !DILocation(line: 20, column: 1, scope: !25)
-// CHECK:STDOUT: !33 = !{!34, !34, i64 0}
-// CHECK:STDOUT: !34 = !{!"p1 _ZTS1Y", !35, i64 0}
-// CHECK:STDOUT: !35 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1Y", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "PassRefExpr", linkageName: "_CPassRefExpr.Main", scope: null, file: !7, line: 6, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{null}
+// CHECK:STDOUT: !18 = !DILocation(line: 7, column: 3, scope: !15)
+// CHECK:STDOUT: !19 = !DILocation(line: 8, column: 3, scope: !15)
+// CHECK:STDOUT: !20 = !DILocation(line: 9, column: 3, scope: !15)
+// CHECK:STDOUT: !21 = !DILocation(line: 10, column: 3, scope: !15)
+// CHECK:STDOUT: !22 = !DILocation(line: 11, column: 3, scope: !15)
+// CHECK:STDOUT: !23 = !DILocation(line: 6, column: 1, scope: !15)
+// CHECK:STDOUT: !24 = distinct !DISubprogram(name: "PassInitExpr", linkageName: "_CPassInitExpr.Main", scope: null, file: !7, line: 16, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !25 = !DILocation(line: 17, column: 19, scope: !24)
+// CHECK:STDOUT: !26 = !DILocation(line: 17, column: 3, scope: !24)
+// CHECK:STDOUT: !27 = !DILocation(line: 16, column: 1, scope: !24)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "PassValueExpr", linkageName: "_CPassValueExpr.Main", scope: null, file: !7, line: 20, type: !29, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !32)
+// CHECK:STDOUT: !29 = !DISubroutineType(types: !30)
+// CHECK:STDOUT: !30 = !{null, !31}
+// CHECK:STDOUT: !31 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !32 = !{!33}
+// CHECK:STDOUT: !33 = !DILocalVariable(arg: 1, scope: !28, type: !31)
+// CHECK:STDOUT: !34 = !DILocation(line: 21, column: 3, scope: !28)
+// CHECK:STDOUT: !35 = !DILocation(line: 20, column: 1, scope: !28)
diff --git a/toolchain/lower/testdata/interop/cpp/pointer.carbon b/toolchain/lower/testdata/interop/cpp/pointer.carbon
index 803b0bc3fc59..2b4b0ee5300b 100644
--- a/toolchain/lower/testdata/interop/cpp/pointer.carbon
+++ b/toolchain/lower/testdata/interop/cpp/pointer.carbon
@@ -95,62 +95,62 @@ fn ReturnPtrWithThunk() -> Core.Optional(Cpp.C*) {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassPtr.Main(ptr %p) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z7TakePtrP1C(ptr %p), !dbg !18
-// CHECK:STDOUT:   ret void, !dbg !19
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z7TakePtrP1C(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnPtr.Main() #0 !dbg !20 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnPtr.call = call ptr @_Z9ReturnPtrv(), !dbg !23
-// CHECK:STDOUT:   ret ptr %ReturnPtr.call, !dbg !24
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z9ReturnPtrv()
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassPtrWithThunk.Main(ptr %p) #0 !dbg !25 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr %p), !dbg !28
-// CHECK:STDOUT:   ret void, !dbg !29
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnPtrWithThunk.Main() #0 !dbg !30 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnPtrWithThunk__carbon_thunk.call = call ptr @_Z18ReturnPtrWithThunki.carbon_thunk0(), !dbg !31
-// CHECK:STDOUT:   ret ptr %ReturnPtrWithThunk__carbon_thunk.call, !dbg !32
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr noundef %0) #1 {
+// CHECK:STDOUT: define dso_local void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !33
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !33
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci(ptr noundef %1, i32 noundef 0)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z16TakePtrWithThunkP1Ci(ptr noundef, i32 noundef) #2
+// CHECK:STDOUT: declare void @_Z16TakePtrWithThunkP1Ci(ptr noundef, i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef ptr @_Z18ReturnPtrWithThunki.carbon_thunk0() #1 {
+// CHECK:STDOUT: define dso_local noundef ptr @_Z18ReturnPtrWithThunki.carbon_thunk0() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %call = call noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef 0)
 // CHECK:STDOUT:   ret ptr %call
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef) #2
+// CHECK:STDOUT: declare noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef) #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassPtr.Main(ptr %p) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z7TakePtrP1C(ptr %p), !dbg !21
+// CHECK:STDOUT:   ret void, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z7TakePtrP1C(ptr noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnPtr.Main() #2 !dbg !23 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %ReturnPtr.call = call ptr @_Z9ReturnPtrv(), !dbg !26
+// CHECK:STDOUT:   ret ptr %ReturnPtr.call, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef ptr @_Z9ReturnPtrv() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassPtrWithThunk.Main(ptr %p) #2 !dbg !28 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr %p), !dbg !31
+// CHECK:STDOUT:   ret void, !dbg !32
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnPtrWithThunk.Main() #2 !dbg !33 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %ReturnPtrWithThunk__carbon_thunk.call = call ptr @_Z18ReturnPtrWithThunki.carbon_thunk0(), !dbg !34
+// CHECK:STDOUT:   ret ptr %ReturnPtrWithThunk__carbon_thunk.call, !dbg !35
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -159,7 +159,7 @@ fn ReturnPtrWithThunk() -> Core.Optional(Cpp.C*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -168,148 +168,148 @@ fn ReturnPtrWithThunk() -> Core.Optional(Cpp.C*) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassPtr", linkageName: "_CPassPtr.Main", scope: null, file: !7, line: 14, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 15, column: 3, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 14, column: 1, scope: !12)
-// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "ReturnPtr", linkageName: "_CReturnPtr.Main", scope: null, file: !7, line: 18, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
-// CHECK:STDOUT: !22 = !{!15}
-// CHECK:STDOUT: !23 = !DILocation(line: 19, column: 10, scope: !20)
-// CHECK:STDOUT: !24 = !DILocation(line: 19, column: 3, scope: !20)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "PassPtrWithThunk", linkageName: "_CPassPtrWithThunk.Main", scope: null, file: !7, line: 22, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !26)
-// CHECK:STDOUT: !26 = !{!27}
-// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !25, type: !15)
-// CHECK:STDOUT: !28 = !DILocation(line: 23, column: 3, scope: !25)
-// CHECK:STDOUT: !29 = !DILocation(line: 22, column: 1, scope: !25)
-// CHECK:STDOUT: !30 = distinct !DISubprogram(name: "ReturnPtrWithThunk", linkageName: "_CReturnPtrWithThunk.Main", scope: null, file: !7, line: 26, type: !21, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !31 = !DILocation(line: 27, column: 10, scope: !30)
-// CHECK:STDOUT: !32 = !DILocation(line: 27, column: 3, scope: !30)
-// CHECK:STDOUT: !33 = !{!34, !34, i64 0}
-// CHECK:STDOUT: !34 = !{!"p1 _ZTS1C", !35, i64 0}
-// CHECK:STDOUT: !35 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "PassPtr", linkageName: "_CPassPtr.Main", scope: null, file: !7, line: 14, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{null, !18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !19 = !{!20}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocation(line: 15, column: 3, scope: !15)
+// CHECK:STDOUT: !22 = !DILocation(line: 14, column: 1, scope: !15)
+// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "ReturnPtr", linkageName: "_CReturnPtr.Main", scope: null, file: !7, line: 18, type: !24, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !24 = !DISubroutineType(types: !25)
+// CHECK:STDOUT: !25 = !{!18}
+// CHECK:STDOUT: !26 = !DILocation(line: 19, column: 10, scope: !23)
+// CHECK:STDOUT: !27 = !DILocation(line: 19, column: 3, scope: !23)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "PassPtrWithThunk", linkageName: "_CPassPtrWithThunk.Main", scope: null, file: !7, line: 22, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !29)
+// CHECK:STDOUT: !29 = !{!30}
+// CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !28, type: !18)
+// CHECK:STDOUT: !31 = !DILocation(line: 23, column: 3, scope: !28)
+// CHECK:STDOUT: !32 = !DILocation(line: 22, column: 1, scope: !28)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "ReturnPtrWithThunk", linkageName: "_CReturnPtrWithThunk.Main", scope: null, file: !7, line: 26, type: !24, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !34 = !DILocation(line: 27, column: 10, scope: !33)
+// CHECK:STDOUT: !35 = !DILocation(line: 27, column: 3, scope: !33)
 // CHECK:STDOUT: ; ModuleID = 'nullable.carbon'
 // CHECK:STDOUT: source_filename = "nullable.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassPtr.Main(ptr %_) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   ret void, !dbg !18
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassNonnullPtr.Main(ptr %p) #0 !dbg !19 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc22_15.2.temp = alloca ptr, align 8, !dbg !22
-// CHECK:STDOUT:   %U.binding.as_type.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %p), !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc22_15.2.temp), !dbg !22
-// CHECK:STDOUT:   store ptr %U.binding.as_type.as.ImplicitAs.impl.Convert.call, ptr %.loc22_15.2.temp, align 8, !dbg !22
-// CHECK:STDOUT:   %.loc22_15.4 = load ptr, ptr %.loc22_15.2.temp, align 8, !dbg !22
-// CHECK:STDOUT:   call void @_Z7TakePtrP1C(ptr %.loc22_15.4), !dbg !23
-// CHECK:STDOUT:   ret void, !dbg !24
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z7TakePtrP1C(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnPtr.Main() #0 !dbg !25 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnPtr.call = call ptr @_Z9ReturnPtrv(), !dbg !28
-// CHECK:STDOUT:   ret ptr %ReturnPtr.call, !dbg !29
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z9ReturnPtrv()
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassPtrWithThunk.Main(ptr %_) #0 !dbg !30 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   ret void, !dbg !33
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassNonnullPtrWithThunk.Main(ptr %p) #0 !dbg !34 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc35_24.2.temp = alloca ptr, align 8, !dbg !37
-// CHECK:STDOUT:   %U.binding.as_type.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %p), !dbg !37
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc35_24.2.temp), !dbg !37
-// CHECK:STDOUT:   store ptr %U.binding.as_type.as.ImplicitAs.impl.Convert.call, ptr %.loc35_24.2.temp, align 8, !dbg !37
-// CHECK:STDOUT:   %.loc35_24.4 = load ptr, ptr %.loc35_24.2.temp, align 8, !dbg !37
-// CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr %.loc35_24.4), !dbg !38
-// CHECK:STDOUT:   ret void, !dbg !39
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define ptr @_CReturnPtrWithThunk.Main() #0 !dbg !40 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnPtrWithThunk__carbon_thunk.call = call ptr @_Z18ReturnPtrWithThunki.carbon_thunk0(), !dbg !41
-// CHECK:STDOUT:   ret ptr %ReturnPtrWithThunk__carbon_thunk.call, !dbg !42
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %self) #0 !dbg !43 {
-// CHECK:STDOUT:   %1 = call ptr @"_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb"(ptr %self), !dbg !49
-// CHECK:STDOUT:   ret ptr %1, !dbg !50
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb"(ptr %self) #0 !dbg !51 {
-// CHECK:STDOUT:   %1 = call ptr @_CSome.Optional.Core.ea71e3f17b6b4efb(ptr %self), !dbg !54
-// CHECK:STDOUT:   ret ptr %1, !dbg !55
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @_CSome.Optional.Core.ea71e3f17b6b4efb(ptr %value) #0 !dbg !56 {
-// CHECK:STDOUT:   %1 = call ptr @"_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655"(ptr %value), !dbg !59
-// CHECK:STDOUT:   ret ptr %1, !dbg !60
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @"_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655"(ptr %self) #0 !dbg !61 {
-// CHECK:STDOUT:   %1 = alloca ptr, align 8, !dbg !64
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %1), !dbg !64
-// CHECK:STDOUT:   store ptr %self, ptr %1, align 8, !dbg !65
-// CHECK:STDOUT:   %2 = load ptr, ptr %1, align 8, !dbg !66
-// CHECK:STDOUT:   ret ptr %2, !dbg !67
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr noundef %0) #2 {
+// CHECK:STDOUT: define dso_local void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !68
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !68
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci(ptr noundef %1, i32 noundef 0)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z16TakePtrWithThunkP1Ci(ptr noundef, i32 noundef) #3
+// CHECK:STDOUT: declare void @_Z16TakePtrWithThunkP1Ci(ptr noundef, i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef ptr @_Z18ReturnPtrWithThunki.carbon_thunk0() #2 {
+// CHECK:STDOUT: define dso_local noundef ptr @_Z18ReturnPtrWithThunki.carbon_thunk0() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %call = call noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef 0)
 // CHECK:STDOUT:   ret ptr %call
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef) #3
+// CHECK:STDOUT: declare noundef ptr @_Z18ReturnPtrWithThunki(i32 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassPtr.Main(ptr %_) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !21
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassNonnullPtr.Main(ptr %p) #2 !dbg !22 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc22_15.2.temp = alloca ptr, align 8, !dbg !25
+// CHECK:STDOUT:   %U.binding.as_type.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %p), !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc22_15.2.temp), !dbg !25
+// CHECK:STDOUT:   store ptr %U.binding.as_type.as.ImplicitAs.impl.Convert.call, ptr %.loc22_15.2.temp, align 8, !dbg !25
+// CHECK:STDOUT:   %.loc22_15.4 = load ptr, ptr %.loc22_15.2.temp, align 8, !dbg !25
+// CHECK:STDOUT:   call void @_Z7TakePtrP1C(ptr %.loc22_15.4), !dbg !26
+// CHECK:STDOUT:   ret void, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z7TakePtrP1C(ptr noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnPtr.Main() #2 !dbg !28 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %ReturnPtr.call = call ptr @_Z9ReturnPtrv(), !dbg !31
+// CHECK:STDOUT:   ret ptr %ReturnPtr.call, !dbg !32
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef ptr @_Z9ReturnPtrv() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassPtrWithThunk.Main(ptr %_) #2 !dbg !33 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !36
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassNonnullPtrWithThunk.Main(ptr %p) #2 !dbg !37 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc35_24.2.temp = alloca ptr, align 8, !dbg !40
+// CHECK:STDOUT:   %U.binding.as_type.as.ImplicitAs.impl.Convert.call = call ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %p), !dbg !40
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc35_24.2.temp), !dbg !40
+// CHECK:STDOUT:   store ptr %U.binding.as_type.as.ImplicitAs.impl.Convert.call, ptr %.loc35_24.2.temp, align 8, !dbg !40
+// CHECK:STDOUT:   %.loc35_24.4 = load ptr, ptr %.loc35_24.2.temp, align 8, !dbg !40
+// CHECK:STDOUT:   call void @_Z16TakePtrWithThunkP1Ci.carbon_thunk1(ptr %.loc35_24.4), !dbg !41
+// CHECK:STDOUT:   ret void, !dbg !42
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define ptr @_CReturnPtrWithThunk.Main() #2 !dbg !43 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %ReturnPtrWithThunk__carbon_thunk.call = call ptr @_Z18ReturnPtrWithThunki.carbon_thunk0(), !dbg !44
+// CHECK:STDOUT:   ret ptr %ReturnPtrWithThunk__carbon_thunk.call, !dbg !45
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41"(ptr %self) #2 !dbg !46 {
+// CHECK:STDOUT:   %1 = call ptr @"_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb"(ptr %self), !dbg !52
+// CHECK:STDOUT:   ret ptr %1, !dbg !53
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb"(ptr %self) #2 !dbg !54 {
+// CHECK:STDOUT:   %1 = call ptr @_CSome.Optional.Core.ea71e3f17b6b4efb(ptr %self), !dbg !57
+// CHECK:STDOUT:   ret ptr %1, !dbg !58
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @_CSome.Optional.Core.ea71e3f17b6b4efb(ptr %value) #2 !dbg !59 {
+// CHECK:STDOUT:   %1 = call ptr @"_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655"(ptr %value), !dbg !62
+// CHECK:STDOUT:   ret ptr %1, !dbg !63
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define linkonce_odr ptr @"_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655"(ptr %self) #2 !dbg !64 {
+// CHECK:STDOUT:   %1 = alloca ptr, align 8, !dbg !67
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %1), !dbg !67
+// CHECK:STDOUT:   store ptr %self, ptr %1, align 8, !dbg !68
+// CHECK:STDOUT:   %2 = load ptr, ptr %1, align 8, !dbg !69
+// CHECK:STDOUT:   ret ptr %2, !dbg !70
+// CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41", { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 0, 2, 1 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -318,7 +318,7 @@ fn ReturnPtrWithThunk() -> Core.Optional(Cpp.C*) {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -327,62 +327,62 @@ fn ReturnPtrWithThunk() -> Core.Optional(Cpp.C*) {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassPtr", linkageName: "_CPassPtr.Main", scope: null, file: !7, line: 14, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 14, column: 1, scope: !12)
-// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "PassNonnullPtr", linkageName: "_CPassNonnullPtr.Main", scope: null, file: !7, line: 19, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !20)
-// CHECK:STDOUT: !20 = !{!21}
-// CHECK:STDOUT: !21 = !DILocalVariable(arg: 1, scope: !19, type: !15)
-// CHECK:STDOUT: !22 = !DILocation(line: 22, column: 15, scope: !19)
-// CHECK:STDOUT: !23 = !DILocation(line: 22, column: 3, scope: !19)
-// CHECK:STDOUT: !24 = !DILocation(line: 19, column: 1, scope: !19)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "ReturnPtr", linkageName: "_CReturnPtr.Main", scope: null, file: !7, line: 25, type: !26, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
-// CHECK:STDOUT: !27 = !{!15}
-// CHECK:STDOUT: !28 = !DILocation(line: 26, column: 10, scope: !25)
-// CHECK:STDOUT: !29 = !DILocation(line: 26, column: 3, scope: !25)
-// CHECK:STDOUT: !30 = distinct !DISubprogram(name: "PassPtrWithThunk", linkageName: "_CPassPtrWithThunk.Main", scope: null, file: !7, line: 29, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !31)
-// CHECK:STDOUT: !31 = !{!32}
-// CHECK:STDOUT: !32 = !DILocalVariable(arg: 1, scope: !30, type: !15)
-// CHECK:STDOUT: !33 = !DILocation(line: 29, column: 1, scope: !30)
-// CHECK:STDOUT: !34 = distinct !DISubprogram(name: "PassNonnullPtrWithThunk", linkageName: "_CPassNonnullPtrWithThunk.Main", scope: null, file: !7, line: 34, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !35)
-// CHECK:STDOUT: !35 = !{!36}
-// CHECK:STDOUT: !36 = !DILocalVariable(arg: 1, scope: !34, type: !15)
-// CHECK:STDOUT: !37 = !DILocation(line: 35, column: 24, scope: !34)
-// CHECK:STDOUT: !38 = !DILocation(line: 35, column: 3, scope: !34)
-// CHECK:STDOUT: !39 = !DILocation(line: 34, column: 1, scope: !34)
-// CHECK:STDOUT: !40 = distinct !DISubprogram(name: "ReturnPtrWithThunk", linkageName: "_CReturnPtrWithThunk.Main", scope: null, file: !7, line: 38, type: !26, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !41 = !DILocation(line: 39, column: 10, scope: !40)
-// CHECK:STDOUT: !42 = !DILocation(line: 39, column: 3, scope: !40)
-// CHECK:STDOUT: !43 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41", scope: null, file: !44, line: 93, type: !45, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !47)
-// CHECK:STDOUT: !44 = !DIFile(filename: "{{.*}}/prelude/types/optional.carbon", directory: "")
-// CHECK:STDOUT: !45 = !DISubroutineType(types: !46)
-// CHECK:STDOUT: !46 = !{!15, !15}
-// CHECK:STDOUT: !47 = !{!48}
-// CHECK:STDOUT: !48 = !DILocalVariable(arg: 1, scope: !43, type: !15)
-// CHECK:STDOUT: !49 = !DILocation(line: 94, column: 12, scope: !43)
-// CHECK:STDOUT: !50 = !DILocation(line: 94, column: 5, scope: !43)
-// CHECK:STDOUT: !51 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb", scope: null, file: !44, line: 68, type: !45, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !52)
-// CHECK:STDOUT: !52 = !{!53}
-// CHECK:STDOUT: !53 = !DILocalVariable(arg: 1, scope: !51, type: !15)
-// CHECK:STDOUT: !54 = !DILocation(line: 69, column: 12, scope: !51)
-// CHECK:STDOUT: !55 = !DILocation(line: 69, column: 5, scope: !51)
-// CHECK:STDOUT: !56 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.Optional.Core.ea71e3f17b6b4efb", scope: null, file: !44, line: 29, type: !45, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !57)
-// CHECK:STDOUT: !57 = !{!58}
-// CHECK:STDOUT: !58 = !DILocalVariable(arg: 1, scope: !56, type: !15)
-// CHECK:STDOUT: !59 = !DILocation(line: 30, column: 12, scope: !56)
-// CHECK:STDOUT: !60 = !DILocation(line: 30, column: 5, scope: !56)
-// CHECK:STDOUT: !61 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655", scope: null, file: !44, line: 138, type: !45, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !62)
-// CHECK:STDOUT: !62 = !{!63}
-// CHECK:STDOUT: !63 = !DILocalVariable(arg: 1, scope: !61, type: !15)
-// CHECK:STDOUT: !64 = !DILocation(line: 139, column: 14, scope: !61)
-// CHECK:STDOUT: !65 = !DILocation(line: 140, column: 5, scope: !61)
-// CHECK:STDOUT: !66 = !DILocation(line: 139, column: 18, scope: !61)
-// CHECK:STDOUT: !67 = !DILocation(line: 141, column: 5, scope: !61)
-// CHECK:STDOUT: !68 = !{!69, !69, i64 0}
-// CHECK:STDOUT: !69 = !{!"p1 _ZTS1C", !70, i64 0}
-// CHECK:STDOUT: !70 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "PassPtr", linkageName: "_CPassPtr.Main", scope: null, file: !7, line: 14, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{null, !18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !19 = !{!20}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocation(line: 14, column: 1, scope: !15)
+// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "PassNonnullPtr", linkageName: "_CPassNonnullPtr.Main", scope: null, file: !7, line: 19, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !23)
+// CHECK:STDOUT: !23 = !{!24}
+// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !22, type: !18)
+// CHECK:STDOUT: !25 = !DILocation(line: 22, column: 15, scope: !22)
+// CHECK:STDOUT: !26 = !DILocation(line: 22, column: 3, scope: !22)
+// CHECK:STDOUT: !27 = !DILocation(line: 19, column: 1, scope: !22)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "ReturnPtr", linkageName: "_CReturnPtr.Main", scope: null, file: !7, line: 25, type: !29, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !29 = !DISubroutineType(types: !30)
+// CHECK:STDOUT: !30 = !{!18}
+// CHECK:STDOUT: !31 = !DILocation(line: 26, column: 10, scope: !28)
+// CHECK:STDOUT: !32 = !DILocation(line: 26, column: 3, scope: !28)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "PassPtrWithThunk", linkageName: "_CPassPtrWithThunk.Main", scope: null, file: !7, line: 29, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !34)
+// CHECK:STDOUT: !34 = !{!35}
+// CHECK:STDOUT: !35 = !DILocalVariable(arg: 1, scope: !33, type: !18)
+// CHECK:STDOUT: !36 = !DILocation(line: 29, column: 1, scope: !33)
+// CHECK:STDOUT: !37 = distinct !DISubprogram(name: "PassNonnullPtrWithThunk", linkageName: "_CPassNonnullPtrWithThunk.Main", scope: null, file: !7, line: 34, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !38)
+// CHECK:STDOUT: !38 = !{!39}
+// CHECK:STDOUT: !39 = !DILocalVariable(arg: 1, scope: !37, type: !18)
+// CHECK:STDOUT: !40 = !DILocation(line: 35, column: 24, scope: !37)
+// CHECK:STDOUT: !41 = !DILocation(line: 35, column: 3, scope: !37)
+// CHECK:STDOUT: !42 = !DILocation(line: 34, column: 1, scope: !37)
+// CHECK:STDOUT: !43 = distinct !DISubprogram(name: "ReturnPtrWithThunk", linkageName: "_CReturnPtrWithThunk.Main", scope: null, file: !7, line: 38, type: !29, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !44 = !DILocation(line: 39, column: 10, scope: !43)
+// CHECK:STDOUT: !45 = !DILocation(line: 39, column: 3, scope: !43)
+// CHECK:STDOUT: !46 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.5b1b7c6bb83e5c41", scope: null, file: !47, line: 93, type: !48, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !50)
+// CHECK:STDOUT: !47 = !DIFile(filename: "{{.*}}/prelude/types/optional.carbon", directory: "")
+// CHECK:STDOUT: !48 = !DISubroutineType(types: !49)
+// CHECK:STDOUT: !49 = !{!18, !18}
+// CHECK:STDOUT: !50 = !{!51}
+// CHECK:STDOUT: !51 = !DILocalVariable(arg: 1, scope: !46, type: !18)
+// CHECK:STDOUT: !52 = !DILocation(line: 94, column: 12, scope: !46)
+// CHECK:STDOUT: !53 = !DILocation(line: 94, column: 5, scope: !46)
+// CHECK:STDOUT: !54 = distinct !DISubprogram(name: "Convert", linkageName: "_CConvert.90961d7b1ce4f089:OptionalAs.0e326e799dad0c64.Core.ea71e3f17b6b4efb", scope: null, file: !47, line: 68, type: !48, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !55)
+// CHECK:STDOUT: !55 = !{!56}
+// CHECK:STDOUT: !56 = !DILocalVariable(arg: 1, scope: !54, type: !18)
+// CHECK:STDOUT: !57 = !DILocation(line: 69, column: 12, scope: !54)
+// CHECK:STDOUT: !58 = !DILocation(line: 69, column: 5, scope: !54)
+// CHECK:STDOUT: !59 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.Optional.Core.ea71e3f17b6b4efb", scope: null, file: !47, line: 29, type: !48, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !60)
+// CHECK:STDOUT: !60 = !{!61}
+// CHECK:STDOUT: !61 = !DILocalVariable(arg: 1, scope: !59, type: !18)
+// CHECK:STDOUT: !62 = !DILocation(line: 30, column: 12, scope: !59)
+// CHECK:STDOUT: !63 = !DILocation(line: 30, column: 5, scope: !59)
+// CHECK:STDOUT: !64 = distinct !DISubprogram(name: "Some", linkageName: "_CSome.e8f8f92d3d08d149:OptionalStorage.Core.f53db17714b9f655", scope: null, file: !47, line: 138, type: !48, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !65)
+// CHECK:STDOUT: !65 = !{!66}
+// CHECK:STDOUT: !66 = !DILocalVariable(arg: 1, scope: !64, type: !18)
+// CHECK:STDOUT: !67 = !DILocation(line: 139, column: 14, scope: !64)
+// CHECK:STDOUT: !68 = !DILocation(line: 140, column: 5, scope: !64)
+// CHECK:STDOUT: !69 = !DILocation(line: 139, column: 18, scope: !64)
+// CHECK:STDOUT: !70 = !DILocation(line: 141, column: 5, scope: !64)
diff --git a/toolchain/lower/testdata/interop/cpp/reference.carbon b/toolchain/lower/testdata/interop/cpp/reference.carbon
index 431fbaaa7516..7ba27b1e6298 100644
--- a/toolchain/lower/testdata/interop/cpp/reference.carbon
+++ b/toolchain/lower/testdata/interop/cpp/reference.carbon
@@ -135,98 +135,98 @@ fn GetRefs() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @C.val.loc19_18.3 = internal constant {} zeroinitializer
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassRefs.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !15
-// CHECK:STDOUT:   %.loc19_18.2.temp = alloca {}, align 8, !dbg !16
-// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !17
-// CHECK:STDOUT:   %.loc24_22.3.temp = alloca i32, align 4, !dbg !18
-// CHECK:STDOUT:   %.loc25_23.2.temp = alloca i32, align 4, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !15
-// CHECK:STDOUT:   call void @_Z8TakeCRefR1C(ptr %c.var), !dbg !20
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !16
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc19_18.2.temp, ptr align 1 @C.val.loc19_18.3, i64 0, i1 false), !dbg !16
-// CHECK:STDOUT:   call void @_Z9TakeCRRefO1C.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !21
-// CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr %c.var), !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !17
-// CHECK:STDOUT:   call void @_Z10TakeIntRefRi(ptr %n.var), !dbg !23
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_22.3.temp), !dbg !18
-// CHECK:STDOUT:   store i32 42, ptr %.loc24_22.3.temp, align 4, !dbg !18
-// CHECK:STDOUT:   call void @_Z11TakeIntRRefOi.carbon_thunk(ptr %.loc24_22.3.temp), !dbg !24
-// CHECK:STDOUT:   %.loc25_23.1 = load i32, ptr %n.var, align 4, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_23.2.temp), !dbg !19
-// CHECK:STDOUT:   store i32 %.loc25_23.1, ptr %.loc25_23.2.temp, align 4, !dbg !19
-// CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr %.loc25_23.2.temp), !dbg !25
-// CHECK:STDOUT:   ret void, !dbg !26
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z8TakeCRefR1C(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z10TakeIntRefRi(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #2
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefO1C.carbon_thunk(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefO1C.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z9TakeCRRefO1C(ptr noundef nonnull align 1 dereferenceable(1) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z9TakeCRRefO1C(ptr noundef nonnull align 1 dereferenceable(1)) #4
+// CHECK:STDOUT: declare void @_Z9TakeCRRefO1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C(ptr noundef nonnull align 1 dereferenceable(1) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C(ptr noundef nonnull align 1 dereferenceable(1)) #4
+// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi.carbon_thunk(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !30
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !30
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !15
 // CHECK:STDOUT:   call void @_Z11TakeIntRRefOi(ptr noundef nonnull align 4 dereferenceable(4) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi(ptr noundef nonnull align 4 dereferenceable(4)) #4
+// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi(ptr noundef nonnull align 4 dereferenceable(4)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !30
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !30
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !15
 // CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi(ptr noundef nonnull align 4 dereferenceable(4) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi(ptr noundef nonnull align 4 dereferenceable(4)) #4
+// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassRefs.Main() #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !20
+// CHECK:STDOUT:   %.loc19_18.2.temp = alloca {}, align 8, !dbg !21
+// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !22
+// CHECK:STDOUT:   %.loc24_22.3.temp = alloca i32, align 4, !dbg !23
+// CHECK:STDOUT:   %.loc25_23.2.temp = alloca i32, align 4, !dbg !24
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !20
+// CHECK:STDOUT:   call void @_Z8TakeCRefR1C(ptr %c.var), !dbg !25
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !21
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc19_18.2.temp, ptr align 1 @C.val.loc19_18.3, i64 0, i1 false), !dbg !21
+// CHECK:STDOUT:   call void @_Z9TakeCRRefO1C.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !26
+// CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr %c.var), !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !22
+// CHECK:STDOUT:   call void @_Z10TakeIntRefRi(ptr %n.var), !dbg !28
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_22.3.temp), !dbg !23
+// CHECK:STDOUT:   store i32 42, ptr %.loc24_22.3.temp, align 4, !dbg !23
+// CHECK:STDOUT:   call void @_Z11TakeIntRRefOi.carbon_thunk(ptr %.loc24_22.3.temp), !dbg !29
+// CHECK:STDOUT:   %.loc25_23.1 = load i32, ptr %n.var, align 4, !dbg !24
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_23.2.temp), !dbg !24
+// CHECK:STDOUT:   store i32 %.loc25_23.1, ptr %.loc25_23.2.temp, align 4, !dbg !24
+// CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr %.loc25_23.2.temp), !dbg !30
+// CHECK:STDOUT:   ret void, !dbg !31
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z8TakeCRefR1C(ptr noundef nonnull align 1 dereferenceable(1)) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Z10TakeIntRefRi(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -235,7 +235,7 @@ fn GetRefs() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -244,26 +244,26 @@ fn GetRefs() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !7, line: 16, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 17, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 19, column: 17, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 22, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 24, column: 19, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 25, column: 23, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 18, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !DILocation(line: 19, column: 3, scope: !12)
-// CHECK:STDOUT: !22 = !DILocation(line: 20, column: 3, scope: !12)
-// CHECK:STDOUT: !23 = !DILocation(line: 23, column: 3, scope: !12)
-// CHECK:STDOUT: !24 = !DILocation(line: 24, column: 3, scope: !12)
-// CHECK:STDOUT: !25 = !DILocation(line: 25, column: 3, scope: !12)
-// CHECK:STDOUT: !26 = !DILocation(line: 16, column: 1, scope: !12)
-// CHECK:STDOUT: !27 = !{!28, !28, i64 0}
-// CHECK:STDOUT: !28 = !{!"p1 _ZTS1C", !29, i64 0}
-// CHECK:STDOUT: !29 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !30 = !{!31, !31, i64 0}
-// CHECK:STDOUT: !31 = !{!"p1 int", !29, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"p1 int", !14, i64 0}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !7, line: 16, type: !18, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{null}
+// CHECK:STDOUT: !20 = !DILocation(line: 17, column: 3, scope: !17)
+// CHECK:STDOUT: !21 = !DILocation(line: 19, column: 17, scope: !17)
+// CHECK:STDOUT: !22 = !DILocation(line: 22, column: 3, scope: !17)
+// CHECK:STDOUT: !23 = !DILocation(line: 24, column: 19, scope: !17)
+// CHECK:STDOUT: !24 = !DILocation(line: 25, column: 23, scope: !17)
+// CHECK:STDOUT: !25 = !DILocation(line: 18, column: 3, scope: !17)
+// CHECK:STDOUT: !26 = !DILocation(line: 19, column: 3, scope: !17)
+// CHECK:STDOUT: !27 = !DILocation(line: 20, column: 3, scope: !17)
+// CHECK:STDOUT: !28 = !DILocation(line: 23, column: 3, scope: !17)
+// CHECK:STDOUT: !29 = !DILocation(line: 24, column: 3, scope: !17)
+// CHECK:STDOUT: !30 = !DILocation(line: 25, column: 3, scope: !17)
+// CHECK:STDOUT: !31 = !DILocation(line: 16, column: 1, scope: !17)
 // CHECK:STDOUT: ; ModuleID = 'pass_references_via_thunk.carbon'
 // CHECK:STDOUT: source_filename = "pass_references_via_thunk.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -273,124 +273,124 @@ fn GetRefs() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @C.val.loc20_18.3 = internal constant {} zeroinitializer
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassRefs.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !15
-// CHECK:STDOUT:   %.loc20_18.2.temp = alloca {}, align 8, !dbg !16
-// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !17
-// CHECK:STDOUT:   %.loc25_22.3.temp = alloca i32, align 4, !dbg !18
-// CHECK:STDOUT:   %.loc26_23.2.temp = alloca i32, align 4, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !15
-// CHECK:STDOUT:   call void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr %c.var), !dbg !20
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_18.2.temp), !dbg !16
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc20_18.2.temp, ptr align 1 @C.val.loc20_18.3, i64 0, i1 false), !dbg !16
-// CHECK:STDOUT:   call void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr %.loc20_18.2.temp), !dbg !21
-// CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr %c.var), !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !17
-// CHECK:STDOUT:   call void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr %n.var), !dbg !23
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_22.3.temp), !dbg !18
-// CHECK:STDOUT:   store i32 42, ptr %.loc25_22.3.temp, align 4, !dbg !18
-// CHECK:STDOUT:   call void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr %.loc25_22.3.temp), !dbg !24
-// CHECK:STDOUT:   %.loc26_23.1 = load i32, ptr %n.var, align 4, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc26_23.2.temp), !dbg !19
-// CHECK:STDOUT:   store i32 %.loc26_23.1, ptr %.loc26_23.2.temp, align 4, !dbg !19
-// CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr %.loc26_23.2.temp), !dbg !25
-// CHECK:STDOUT:   ret void, !dbg !26
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #2
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr noundef nonnull align 1 dereferenceable(1) %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr noundef nonnull align 1 dereferenceable(1) %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !27, !nonnull !30
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12, !nonnull !15
 // CHECK:STDOUT:   call void @_Z8TakeCRefR1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z8TakeCRefR1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #4
+// CHECK:STDOUT: declare void @_Z8TakeCRefR1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z9TakeCRRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z9TakeCRRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #4
+// CHECK:STDOUT: declare void @_Z9TakeCRRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #4
+// CHECK:STDOUT: declare void @_Z13TakeConstCRefRK1C10ForceThunk(ptr noundef nonnull align 1 dereferenceable(1)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr noundef nonnull align 4 dereferenceable(4) %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr noundef nonnull align 4 dereferenceable(4) %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !31
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !31, !nonnull !30, !align !33
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !16, !nonnull !15, !align !18
 // CHECK:STDOUT:   call void @_Z10TakeIntRefRi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z10TakeIntRefRi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #4
+// CHECK:STDOUT: declare void @_Z10TakeIntRefRi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !31
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !31
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !16
 // CHECK:STDOUT:   call void @_Z11TakeIntRRefOi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #4
+// CHECK:STDOUT: declare void @_Z11TakeIntRRefOi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !31
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !31
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !16
 // CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4) %1)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #4
+// CHECK:STDOUT: declare void @_Z15TakeConstIntRefRKi10ForceThunk(ptr noundef nonnull align 4 dereferenceable(4)) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassRefs.Main() #2 !dbg !19 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %c.var = alloca {}, align 8, !dbg !22
+// CHECK:STDOUT:   %.loc20_18.2.temp = alloca {}, align 8, !dbg !23
+// CHECK:STDOUT:   %n.var = alloca i32, align 4, !dbg !24
+// CHECK:STDOUT:   %.loc25_22.3.temp = alloca i32, align 4, !dbg !25
+// CHECK:STDOUT:   %.loc26_23.2.temp = alloca i32, align 4, !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !22
+// CHECK:STDOUT:   call void @_Z8TakeCRefR1C10ForceThunk.carbon_thunk1(ptr %c.var), !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_18.2.temp), !dbg !23
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc20_18.2.temp, ptr align 1 @C.val.loc20_18.3, i64 0, i1 false), !dbg !23
+// CHECK:STDOUT:   call void @_Z9TakeCRRefRK1C10ForceThunk.carbon_thunk1(ptr %.loc20_18.2.temp), !dbg !28
+// CHECK:STDOUT:   call void @_Z13TakeConstCRefRK1C10ForceThunk.carbon_thunk1(ptr %c.var), !dbg !29
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !24
+// CHECK:STDOUT:   call void @_Z10TakeIntRefRi10ForceThunk.carbon_thunk1(ptr %n.var), !dbg !30
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_22.3.temp), !dbg !25
+// CHECK:STDOUT:   store i32 42, ptr %.loc25_22.3.temp, align 4, !dbg !25
+// CHECK:STDOUT:   call void @_Z11TakeIntRRefOi10ForceThunk.carbon_thunk1(ptr %.loc25_22.3.temp), !dbg !31
+// CHECK:STDOUT:   %.loc26_23.1 = load i32, ptr %n.var, align 4, !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc26_23.2.temp), !dbg !26
+// CHECK:STDOUT:   store i32 %.loc26_23.1, ptr %.loc26_23.2.temp, align 4, !dbg !26
+// CHECK:STDOUT:   call void @_Z15TakeConstIntRefRKi10ForceThunk.carbon_thunk1(ptr %.loc26_23.2.temp), !dbg !32
+// CHECK:STDOUT:   ret void, !dbg !33
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -399,7 +399,7 @@ fn GetRefs() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -408,28 +408,28 @@ fn GetRefs() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !7, line: 17, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 18, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 20, column: 17, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 23, column: 3, scope: !12)
-// CHECK:STDOUT: !18 = !DILocation(line: 25, column: 19, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 26, column: 23, scope: !12)
-// CHECK:STDOUT: !20 = !DILocation(line: 19, column: 3, scope: !12)
-// CHECK:STDOUT: !21 = !DILocation(line: 20, column: 3, scope: !12)
-// CHECK:STDOUT: !22 = !DILocation(line: 21, column: 3, scope: !12)
-// CHECK:STDOUT: !23 = !DILocation(line: 24, column: 3, scope: !12)
-// CHECK:STDOUT: !24 = !DILocation(line: 25, column: 3, scope: !12)
-// CHECK:STDOUT: !25 = !DILocation(line: 26, column: 3, scope: !12)
-// CHECK:STDOUT: !26 = !DILocation(line: 17, column: 1, scope: !12)
-// CHECK:STDOUT: !27 = !{!28, !28, i64 0}
-// CHECK:STDOUT: !28 = !{!"p1 _ZTS1C", !29, i64 0}
-// CHECK:STDOUT: !29 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !30 = !{}
-// CHECK:STDOUT: !31 = !{!32, !32, i64 0}
-// CHECK:STDOUT: !32 = !{!"p1 int", !29, i64 0}
-// CHECK:STDOUT: !33 = !{i64 4}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{}
+// CHECK:STDOUT: !16 = !{!17, !17, i64 0}
+// CHECK:STDOUT: !17 = !{!"p1 int", !14, i64 0}
+// CHECK:STDOUT: !18 = !{i64 4}
+// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !7, line: 17, type: !20, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !20 = !DISubroutineType(types: !21)
+// CHECK:STDOUT: !21 = !{null}
+// CHECK:STDOUT: !22 = !DILocation(line: 18, column: 3, scope: !19)
+// CHECK:STDOUT: !23 = !DILocation(line: 20, column: 17, scope: !19)
+// CHECK:STDOUT: !24 = !DILocation(line: 23, column: 3, scope: !19)
+// CHECK:STDOUT: !25 = !DILocation(line: 25, column: 19, scope: !19)
+// CHECK:STDOUT: !26 = !DILocation(line: 26, column: 23, scope: !19)
+// CHECK:STDOUT: !27 = !DILocation(line: 19, column: 3, scope: !19)
+// CHECK:STDOUT: !28 = !DILocation(line: 20, column: 3, scope: !19)
+// CHECK:STDOUT: !29 = !DILocation(line: 21, column: 3, scope: !19)
+// CHECK:STDOUT: !30 = !DILocation(line: 24, column: 3, scope: !19)
+// CHECK:STDOUT: !31 = !DILocation(line: 25, column: 3, scope: !19)
+// CHECK:STDOUT: !32 = !DILocation(line: 26, column: 3, scope: !19)
+// CHECK:STDOUT: !33 = !DILocation(line: 17, column: 1, scope: !19)
 // CHECK:STDOUT: ; ModuleID = 'return_references.carbon'
 // CHECK:STDOUT: source_filename = "return_references.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -447,19 +447,20 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void, !dbg !21
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z10ReturnCRefv()
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRefv() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z11ReturnCRRefv()
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRefv() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z15ReturnConstCRefv()
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRefv() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z12ReturnIntRefv()
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRefv() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z13ReturnIntRRefv()
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRefv() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z17ReturnConstIntRefv()
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRefv() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -468,7 +469,7 @@ fn GetRefs() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -494,8 +495,68 @@ fn GetRefs() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %class.ForceThunk = type { i8 }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk.carbon_thunk0() #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
+// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk()
+// CHECK:STDOUT:   ret ptr %call
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk() #1
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CGetRefs.Main() #0 !dbg !12 {
+// CHECK:STDOUT: define void @_CGetRefs.Main() #2 !dbg !12 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %ReturnCRef__carbon_thunk.call = call ptr @_Z10ReturnCRef10ForceThunk.carbon_thunk0(), !dbg !15
 // CHECK:STDOUT:   %ReturnCRRef__carbon_thunk.call = call ptr @_Z11ReturnCRRef10ForceThunk.carbon_thunk0(), !dbg !16
@@ -506,69 +567,9 @@ fn GetRefs() {
 // CHECK:STDOUT:   ret void, !dbg !21
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z10ReturnCRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 1 dereferenceable(1) ptr @_Z15ReturnConstCRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z12ReturnIntRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z13ReturnIntRRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk.carbon_thunk0() #1 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %agg.tmp = alloca %class.ForceThunk, align 1
-// CHECK:STDOUT:   %call = call noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk()
-// CHECK:STDOUT:   ret ptr %call
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef nonnull align 4 dereferenceable(4) ptr @_Z17ReturnConstIntRef10ForceThunk() #2
-// CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -577,7 +578,7 @@ fn GetRefs() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
diff --git a/toolchain/lower/testdata/interop/cpp/return.carbon b/toolchain/lower/testdata/interop/cpp/return.carbon
index 6d9009f1c127..eb3982ae0d37 100644
--- a/toolchain/lower/testdata/interop/cpp/return.carbon
+++ b/toolchain/lower/testdata/interop/cpp/return.carbon
@@ -117,232 +117,232 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i8 @_CGetU8.Main() #0 !dbg !12 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z8ReturnU8v.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc6_40.1.temp = alloca i8, align 1, !dbg !16
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc6_40.1.temp), !dbg !16
-// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc6_40.1.temp), !dbg !16
-// CHECK:STDOUT:   %.loc6_40.2 = load i8, ptr %.loc6_40.1.temp, align 1, !dbg !16
-// CHECK:STDOUT:   ret i8 %.loc6_40.2, !dbg !17
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %call = call noundef zeroext i8 @_Z8ReturnU8v()
+// CHECK:STDOUT:   store i8 %call, ptr %0, align 1, !tbaa !15
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef zeroext i8 @_Z8ReturnU8v() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z9ReturnU16v.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %call = call noundef zeroext i16 @_Z9ReturnU16v()
+// CHECK:STDOUT:   store i16 %call, ptr %0, align 2, !tbaa !18
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef zeroext i16 @_Z9ReturnU16v() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z8ReturnI8v.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %call = call noundef signext i8 @_Z8ReturnI8v()
+// CHECK:STDOUT:   store i8 %call, ptr %0, align 1, !tbaa !15
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef signext i8 @_Z8ReturnI8v() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
+// CHECK:STDOUT: define dso_local void @_Z9ReturnI16v.carbon_thunk(ptr noundef %return) #0 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %call = call noundef signext i16 @_Z9ReturnI16v()
+// CHECK:STDOUT:   store i16 %call, ptr %0, align 2, !tbaa !18
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare noundef signext i16 @_Z9ReturnI16v() #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i8 @_CGetU8.Main() #2 !dbg !20 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc6_40.1.temp = alloca i8, align 1, !dbg !24
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc6_40.1.temp), !dbg !24
+// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc6_40.1.temp), !dbg !24
+// CHECK:STDOUT:   %.loc6_40.2 = load i8, ptr %.loc6_40.1.temp, align 1, !dbg !24
+// CHECK:STDOUT:   ret i8 %.loc6_40.2, !dbg !25
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i16 @_CGetU16.Main() #0 !dbg !18 {
+// CHECK:STDOUT: define i16 @_CGetU16.Main() #2 !dbg !26 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc7_43.1.temp = alloca i16, align 2, !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_43.1.temp), !dbg !22
-// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc7_43.1.temp), !dbg !22
-// CHECK:STDOUT:   %.loc7_43.2 = load i16, ptr %.loc7_43.1.temp, align 2, !dbg !22
-// CHECK:STDOUT:   ret i16 %.loc7_43.2, !dbg !23
+// CHECK:STDOUT:   %.loc7_43.1.temp = alloca i16, align 2, !dbg !30
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc7_43.1.temp), !dbg !30
+// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc7_43.1.temp), !dbg !30
+// CHECK:STDOUT:   %.loc7_43.2 = load i16, ptr %.loc7_43.1.temp, align 2, !dbg !30
+// CHECK:STDOUT:   ret i16 %.loc7_43.2, !dbg !31
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CGetU32.Main() #0 !dbg !24 {
+// CHECK:STDOUT: define i32 @_CGetU32.Main() #2 !dbg !32 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !28
-// CHECK:STDOUT:   ret i32 %ReturnU32.call, !dbg !29
+// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !36
+// CHECK:STDOUT:   ret i32 %ReturnU32.call, !dbg !37
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare i32 @_Z9ReturnU32v()
+// CHECK:STDOUT: declare noundef i32 @_Z9ReturnU32v() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i64 @_CGetU64.Main() #0 !dbg !30 {
+// CHECK:STDOUT: define i64 @_CGetU64.Main() #2 !dbg !38 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !34
-// CHECK:STDOUT:   ret i64 %ReturnU64.call, !dbg !35
+// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !42
+// CHECK:STDOUT:   ret i64 %ReturnU64.call, !dbg !43
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare i64 @_Z9ReturnU64v()
+// CHECK:STDOUT: declare noundef i64 @_Z9ReturnU64v() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i8 @_CGetI8.Main() #0 !dbg !36 {
+// CHECK:STDOUT: define i8 @_CGetI8.Main() #2 !dbg !44 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc11_40.1.temp = alloca i8, align 1, !dbg !40
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc11_40.1.temp), !dbg !40
-// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc11_40.1.temp), !dbg !40
-// CHECK:STDOUT:   %.loc11_40.2 = load i8, ptr %.loc11_40.1.temp, align 1, !dbg !40
-// CHECK:STDOUT:   ret i8 %.loc11_40.2, !dbg !41
+// CHECK:STDOUT:   %.loc11_40.1.temp = alloca i8, align 1, !dbg !48
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc11_40.1.temp), !dbg !48
+// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc11_40.1.temp), !dbg !48
+// CHECK:STDOUT:   %.loc11_40.2 = load i8, ptr %.loc11_40.1.temp, align 1, !dbg !48
+// CHECK:STDOUT:   ret i8 %.loc11_40.2, !dbg !49
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i16 @_CGetI16.Main() #0 !dbg !42 {
+// CHECK:STDOUT: define i16 @_CGetI16.Main() #2 !dbg !50 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc12_43.1.temp = alloca i16, align 2, !dbg !46
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_43.1.temp), !dbg !46
-// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc12_43.1.temp), !dbg !46
-// CHECK:STDOUT:   %.loc12_43.2 = load i16, ptr %.loc12_43.1.temp, align 2, !dbg !46
-// CHECK:STDOUT:   ret i16 %.loc12_43.2, !dbg !47
+// CHECK:STDOUT:   %.loc12_43.1.temp = alloca i16, align 2, !dbg !54
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_43.1.temp), !dbg !54
+// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc12_43.1.temp), !dbg !54
+// CHECK:STDOUT:   %.loc12_43.2 = load i16, ptr %.loc12_43.1.temp, align 2, !dbg !54
+// CHECK:STDOUT:   ret i16 %.loc12_43.2, !dbg !55
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CGetI32.Main() #0 !dbg !48 {
+// CHECK:STDOUT: define i32 @_CGetI32.Main() #2 !dbg !56 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !52
-// CHECK:STDOUT:   ret i32 %ReturnI32.call, !dbg !53
+// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !60
+// CHECK:STDOUT:   ret i32 %ReturnI32.call, !dbg !61
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare i32 @_Z9ReturnI32v()
+// CHECK:STDOUT: declare noundef i32 @_Z9ReturnI32v() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i64 @_CGetI64.Main() #0 !dbg !54 {
+// CHECK:STDOUT: define i64 @_CGetI64.Main() #2 !dbg !62 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !58
-// CHECK:STDOUT:   ret i64 %ReturnI64.call, !dbg !59
+// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !66
+// CHECK:STDOUT:   ret i64 %ReturnI64.call, !dbg !67
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare i64 @_Z9ReturnI64v()
+// CHECK:STDOUT: declare noundef i64 @_Z9ReturnI64v() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_CUse.Main(i8, i16, i32, i64, i8, i16, i32, i64)
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CLets.Main() #0 !dbg !60 {
+// CHECK:STDOUT: define void @_CLets.Main() #2 !dbg !68 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc19_32.1.temp = alloca i8, align 1, !dbg !63
-// CHECK:STDOUT:   %.loc20_35.1.temp = alloca i16, align 2, !dbg !64
-// CHECK:STDOUT:   %.loc24_32.1.temp = alloca i8, align 1, !dbg !65
-// CHECK:STDOUT:   %.loc25_35.1.temp = alloca i16, align 2, !dbg !66
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_32.1.temp), !dbg !63
-// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc19_32.1.temp), !dbg !63
-// CHECK:STDOUT:   %.loc19_32.2 = load i8, ptr %.loc19_32.1.temp, align 1, !dbg !63
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_35.1.temp), !dbg !64
-// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc20_35.1.temp), !dbg !64
-// CHECK:STDOUT:   %.loc20_35.2 = load i16, ptr %.loc20_35.1.temp, align 2, !dbg !64
-// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !67
-// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !68
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_32.1.temp), !dbg !65
-// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc24_32.1.temp), !dbg !65
-// CHECK:STDOUT:   %.loc24_32.2 = load i8, ptr %.loc24_32.1.temp, align 1, !dbg !65
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_35.1.temp), !dbg !66
-// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc25_35.1.temp), !dbg !66
-// CHECK:STDOUT:   %.loc25_35.2 = load i16, ptr %.loc25_35.1.temp, align 2, !dbg !66
-// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !69
-// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !70
-// CHECK:STDOUT:   call void @_CUse.Main(i8 %.loc19_32.2, i16 %.loc20_35.2, i32 %ReturnU32.call, i64 %ReturnU64.call, i8 %.loc24_32.2, i16 %.loc25_35.2, i32 %ReturnI32.call, i64 %ReturnI64.call), !dbg !71
-// CHECK:STDOUT:   ret void, !dbg !72
+// CHECK:STDOUT:   %.loc19_32.1.temp = alloca i8, align 1, !dbg !71
+// CHECK:STDOUT:   %.loc20_35.1.temp = alloca i16, align 2, !dbg !72
+// CHECK:STDOUT:   %.loc24_32.1.temp = alloca i8, align 1, !dbg !73
+// CHECK:STDOUT:   %.loc25_35.1.temp = alloca i16, align 2, !dbg !74
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc19_32.1.temp), !dbg !71
+// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc19_32.1.temp), !dbg !71
+// CHECK:STDOUT:   %.loc19_32.2 = load i8, ptr %.loc19_32.1.temp, align 1, !dbg !71
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc20_35.1.temp), !dbg !72
+// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc20_35.1.temp), !dbg !72
+// CHECK:STDOUT:   %.loc20_35.2 = load i16, ptr %.loc20_35.1.temp, align 2, !dbg !72
+// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !75
+// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !76
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_32.1.temp), !dbg !73
+// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc24_32.1.temp), !dbg !73
+// CHECK:STDOUT:   %.loc24_32.2 = load i8, ptr %.loc24_32.1.temp, align 1, !dbg !73
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc25_35.1.temp), !dbg !74
+// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc25_35.1.temp), !dbg !74
+// CHECK:STDOUT:   %.loc25_35.2 = load i16, ptr %.loc25_35.1.temp, align 2, !dbg !74
+// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !77
+// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !78
+// CHECK:STDOUT:   call void @_CUse.Main(i8 %.loc19_32.2, i16 %.loc20_35.2, i32 %ReturnU32.call, i64 %ReturnU64.call, i8 %.loc24_32.2, i16 %.loc25_35.2, i32 %ReturnI32.call, i64 %ReturnI64.call), !dbg !79
+// CHECK:STDOUT:   ret void, !dbg !80
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CVars.Main() #0 !dbg !73 {
+// CHECK:STDOUT: define void @_CVars.Main() #2 !dbg !81 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %my_u8.var = alloca i8, align 1, !dbg !74
-// CHECK:STDOUT:   %.loc33_32.1.temp = alloca i8, align 1, !dbg !75
-// CHECK:STDOUT:   %my_u16.var = alloca i16, align 2, !dbg !76
-// CHECK:STDOUT:   %.loc34_35.1.temp = alloca i16, align 2, !dbg !77
-// CHECK:STDOUT:   %my_u32.var = alloca i32, align 4, !dbg !78
-// CHECK:STDOUT:   %my_u64.var = alloca i64, align 8, !dbg !79
-// CHECK:STDOUT:   %my_i8.var = alloca i8, align 1, !dbg !80
-// CHECK:STDOUT:   %.loc38_32.1.temp = alloca i8, align 1, !dbg !81
-// CHECK:STDOUT:   %my_i16.var = alloca i16, align 2, !dbg !82
-// CHECK:STDOUT:   %.loc39_35.1.temp = alloca i16, align 2, !dbg !83
-// CHECK:STDOUT:   %my_i32.var = alloca i32, align 4, !dbg !84
-// CHECK:STDOUT:   %my_i64.var = alloca i64, align 8, !dbg !85
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u8.var), !dbg !74
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc33_32.1.temp), !dbg !75
-// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc33_32.1.temp), !dbg !75
-// CHECK:STDOUT:   %.loc33_32.2 = load i8, ptr %.loc33_32.1.temp, align 1, !dbg !75
-// CHECK:STDOUT:   store i8 %.loc33_32.2, ptr %my_u8.var, align 1, !dbg !74
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u16.var), !dbg !76
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc34_35.1.temp), !dbg !77
-// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc34_35.1.temp), !dbg !77
-// CHECK:STDOUT:   %.loc34_35.2 = load i16, ptr %.loc34_35.1.temp, align 2, !dbg !77
-// CHECK:STDOUT:   store i16 %.loc34_35.2, ptr %my_u16.var, align 2, !dbg !76
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u32.var), !dbg !78
-// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !86
-// CHECK:STDOUT:   store i32 %ReturnU32.call, ptr %my_u32.var, align 4, !dbg !78
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u64.var), !dbg !79
-// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !87
-// CHECK:STDOUT:   store i64 %ReturnU64.call, ptr %my_u64.var, align 4, !dbg !79
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i8.var), !dbg !80
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc38_32.1.temp), !dbg !81
-// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc38_32.1.temp), !dbg !81
-// CHECK:STDOUT:   %.loc38_32.2 = load i8, ptr %.loc38_32.1.temp, align 1, !dbg !81
-// CHECK:STDOUT:   store i8 %.loc38_32.2, ptr %my_i8.var, align 1, !dbg !80
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i16.var), !dbg !82
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc39_35.1.temp), !dbg !83
-// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc39_35.1.temp), !dbg !83
-// CHECK:STDOUT:   %.loc39_35.2 = load i16, ptr %.loc39_35.1.temp, align 2, !dbg !83
-// CHECK:STDOUT:   store i16 %.loc39_35.2, ptr %my_i16.var, align 2, !dbg !82
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i32.var), !dbg !84
-// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !88
-// CHECK:STDOUT:   store i32 %ReturnI32.call, ptr %my_i32.var, align 4, !dbg !84
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i64.var), !dbg !85
-// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !89
-// CHECK:STDOUT:   store i64 %ReturnI64.call, ptr %my_i64.var, align 4, !dbg !85
-// CHECK:STDOUT:   %.loc43_7 = load i8, ptr %my_u8.var, align 1, !dbg !90
-// CHECK:STDOUT:   %.loc43_14 = load i16, ptr %my_u16.var, align 2, !dbg !91
-// CHECK:STDOUT:   %.loc43_22 = load i32, ptr %my_u32.var, align 4, !dbg !92
-// CHECK:STDOUT:   %.loc43_30 = load i64, ptr %my_u64.var, align 4, !dbg !93
-// CHECK:STDOUT:   %.loc43_38 = load i8, ptr %my_i8.var, align 1, !dbg !94
-// CHECK:STDOUT:   %.loc43_45 = load i16, ptr %my_i16.var, align 2, !dbg !95
-// CHECK:STDOUT:   %.loc43_53 = load i32, ptr %my_i32.var, align 4, !dbg !96
-// CHECK:STDOUT:   %.loc43_61 = load i64, ptr %my_i64.var, align 4, !dbg !97
-// CHECK:STDOUT:   call void @_CUse.Main(i8 %.loc43_7, i16 %.loc43_14, i32 %.loc43_22, i64 %.loc43_30, i8 %.loc43_38, i16 %.loc43_45, i32 %.loc43_53, i64 %.loc43_61), !dbg !98
-// CHECK:STDOUT:   ret void, !dbg !99
+// CHECK:STDOUT:   %my_u8.var = alloca i8, align 1, !dbg !82
+// CHECK:STDOUT:   %.loc33_32.1.temp = alloca i8, align 1, !dbg !83
+// CHECK:STDOUT:   %my_u16.var = alloca i16, align 2, !dbg !84
+// CHECK:STDOUT:   %.loc34_35.1.temp = alloca i16, align 2, !dbg !85
+// CHECK:STDOUT:   %my_u32.var = alloca i32, align 4, !dbg !86
+// CHECK:STDOUT:   %my_u64.var = alloca i64, align 8, !dbg !87
+// CHECK:STDOUT:   %my_i8.var = alloca i8, align 1, !dbg !88
+// CHECK:STDOUT:   %.loc38_32.1.temp = alloca i8, align 1, !dbg !89
+// CHECK:STDOUT:   %my_i16.var = alloca i16, align 2, !dbg !90
+// CHECK:STDOUT:   %.loc39_35.1.temp = alloca i16, align 2, !dbg !91
+// CHECK:STDOUT:   %my_i32.var = alloca i32, align 4, !dbg !92
+// CHECK:STDOUT:   %my_i64.var = alloca i64, align 8, !dbg !93
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u8.var), !dbg !82
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc33_32.1.temp), !dbg !83
+// CHECK:STDOUT:   call void @_Z8ReturnU8v.carbon_thunk(ptr %.loc33_32.1.temp), !dbg !83
+// CHECK:STDOUT:   %.loc33_32.2 = load i8, ptr %.loc33_32.1.temp, align 1, !dbg !83
+// CHECK:STDOUT:   store i8 %.loc33_32.2, ptr %my_u8.var, align 1, !dbg !82
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u16.var), !dbg !84
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc34_35.1.temp), !dbg !85
+// CHECK:STDOUT:   call void @_Z9ReturnU16v.carbon_thunk(ptr %.loc34_35.1.temp), !dbg !85
+// CHECK:STDOUT:   %.loc34_35.2 = load i16, ptr %.loc34_35.1.temp, align 2, !dbg !85
+// CHECK:STDOUT:   store i16 %.loc34_35.2, ptr %my_u16.var, align 2, !dbg !84
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u32.var), !dbg !86
+// CHECK:STDOUT:   %ReturnU32.call = call i32 @_Z9ReturnU32v(), !dbg !94
+// CHECK:STDOUT:   store i32 %ReturnU32.call, ptr %my_u32.var, align 4, !dbg !86
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_u64.var), !dbg !87
+// CHECK:STDOUT:   %ReturnU64.call = call i64 @_Z9ReturnU64v(), !dbg !95
+// CHECK:STDOUT:   store i64 %ReturnU64.call, ptr %my_u64.var, align 8, !dbg !87
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i8.var), !dbg !88
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc38_32.1.temp), !dbg !89
+// CHECK:STDOUT:   call void @_Z8ReturnI8v.carbon_thunk(ptr %.loc38_32.1.temp), !dbg !89
+// CHECK:STDOUT:   %.loc38_32.2 = load i8, ptr %.loc38_32.1.temp, align 1, !dbg !89
+// CHECK:STDOUT:   store i8 %.loc38_32.2, ptr %my_i8.var, align 1, !dbg !88
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i16.var), !dbg !90
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc39_35.1.temp), !dbg !91
+// CHECK:STDOUT:   call void @_Z9ReturnI16v.carbon_thunk(ptr %.loc39_35.1.temp), !dbg !91
+// CHECK:STDOUT:   %.loc39_35.2 = load i16, ptr %.loc39_35.1.temp, align 2, !dbg !91
+// CHECK:STDOUT:   store i16 %.loc39_35.2, ptr %my_i16.var, align 2, !dbg !90
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i32.var), !dbg !92
+// CHECK:STDOUT:   %ReturnI32.call = call i32 @_Z9ReturnI32v(), !dbg !96
+// CHECK:STDOUT:   store i32 %ReturnI32.call, ptr %my_i32.var, align 4, !dbg !92
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %my_i64.var), !dbg !93
+// CHECK:STDOUT:   %ReturnI64.call = call i64 @_Z9ReturnI64v(), !dbg !97
+// CHECK:STDOUT:   store i64 %ReturnI64.call, ptr %my_i64.var, align 8, !dbg !93
+// CHECK:STDOUT:   %.loc43_7 = load i8, ptr %my_u8.var, align 1, !dbg !98
+// CHECK:STDOUT:   %.loc43_14 = load i16, ptr %my_u16.var, align 2, !dbg !99
+// CHECK:STDOUT:   %.loc43_22 = load i32, ptr %my_u32.var, align 4, !dbg !100
+// CHECK:STDOUT:   %.loc43_30 = load i64, ptr %my_u64.var, align 8, !dbg !101
+// CHECK:STDOUT:   %.loc43_38 = load i8, ptr %my_i8.var, align 1, !dbg !102
+// CHECK:STDOUT:   %.loc43_45 = load i16, ptr %my_i16.var, align 2, !dbg !103
+// CHECK:STDOUT:   %.loc43_53 = load i32, ptr %my_i32.var, align 4, !dbg !104
+// CHECK:STDOUT:   %.loc43_61 = load i64, ptr %my_i64.var, align 8, !dbg !105
+// CHECK:STDOUT:   call void @_CUse.Main(i8 %.loc43_7, i16 %.loc43_14, i32 %.loc43_22, i64 %.loc43_30, i8 %.loc43_38, i16 %.loc43_45, i32 %.loc43_53, i64 %.loc43_61), !dbg !106
+// CHECK:STDOUT:   ret void, !dbg !107
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z8ReturnU8v.carbon_thunk(ptr noundef %return) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !100
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !100
-// CHECK:STDOUT:   %call = call noundef zeroext i8 @_Z8ReturnU8v()
-// CHECK:STDOUT:   store i8 %call, ptr %0, align 1, !tbaa !103
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef zeroext i8 @_Z8ReturnU8v() #3
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9ReturnU16v.carbon_thunk(ptr noundef %return) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !104
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !104
-// CHECK:STDOUT:   %call = call noundef zeroext i16 @_Z9ReturnU16v()
-// CHECK:STDOUT:   store i16 %call, ptr %0, align 2, !tbaa !106
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef zeroext i16 @_Z9ReturnU16v() #3
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z8ReturnI8v.carbon_thunk(ptr noundef %return) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !100
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !100
-// CHECK:STDOUT:   %call = call noundef signext i8 @_Z8ReturnI8v()
-// CHECK:STDOUT:   store i8 %call, ptr %0, align 1, !tbaa !103
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef signext i8 @_Z8ReturnI8v() #3
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z9ReturnI16v.carbon_thunk(ptr noundef %return) #2 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !104
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !104
-// CHECK:STDOUT:   %call = call noundef signext i16 @_Z9ReturnI16v()
-// CHECK:STDOUT:   store i16 %call, ptr %0, align 2, !tbaa !106
-// CHECK:STDOUT:   ret void
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare noundef signext i16 @_Z9ReturnI16v() #3
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -351,7 +351,7 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -360,102 +360,102 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "GetU8", linkageName: "_CGetU8.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15}
-// CHECK:STDOUT: !15 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 27, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 6, column: 20, scope: !12)
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "GetU16", linkageName: "_CGetU16.Main", scope: null, file: !7, line: 7, type: !19, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
-// CHECK:STDOUT: !20 = !{!21}
-// CHECK:STDOUT: !21 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !22 = !DILocation(line: 7, column: 29, scope: !18)
-// CHECK:STDOUT: !23 = !DILocation(line: 7, column: 22, scope: !18)
-// CHECK:STDOUT: !24 = distinct !DISubprogram(name: "GetU32", linkageName: "_CGetU32.Main", scope: null, file: !7, line: 8, type: !25, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !25 = !DISubroutineType(types: !26)
-// CHECK:STDOUT: !26 = !{!27}
-// CHECK:STDOUT: !27 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !28 = !DILocation(line: 8, column: 29, scope: !24)
-// CHECK:STDOUT: !29 = !DILocation(line: 8, column: 22, scope: !24)
-// CHECK:STDOUT: !30 = distinct !DISubprogram(name: "GetU64", linkageName: "_CGetU64.Main", scope: null, file: !7, line: 9, type: !31, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !31 = !DISubroutineType(types: !32)
-// CHECK:STDOUT: !32 = !{!33}
-// CHECK:STDOUT: !33 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_unsigned)
-// CHECK:STDOUT: !34 = !DILocation(line: 9, column: 29, scope: !30)
-// CHECK:STDOUT: !35 = !DILocation(line: 9, column: 22, scope: !30)
-// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "GetI8", linkageName: "_CGetI8.Main", scope: null, file: !7, line: 11, type: !37, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !37 = !DISubroutineType(types: !38)
-// CHECK:STDOUT: !38 = !{!39}
-// CHECK:STDOUT: !39 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !40 = !DILocation(line: 11, column: 27, scope: !36)
-// CHECK:STDOUT: !41 = !DILocation(line: 11, column: 20, scope: !36)
-// CHECK:STDOUT: !42 = distinct !DISubprogram(name: "GetI16", linkageName: "_CGetI16.Main", scope: null, file: !7, line: 12, type: !43, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !43 = !DISubroutineType(types: !44)
-// CHECK:STDOUT: !44 = !{!45}
-// CHECK:STDOUT: !45 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !46 = !DILocation(line: 12, column: 29, scope: !42)
-// CHECK:STDOUT: !47 = !DILocation(line: 12, column: 22, scope: !42)
-// CHECK:STDOUT: !48 = distinct !DISubprogram(name: "GetI32", linkageName: "_CGetI32.Main", scope: null, file: !7, line: 13, type: !49, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !49 = !DISubroutineType(types: !50)
-// CHECK:STDOUT: !50 = !{!51}
-// CHECK:STDOUT: !51 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !52 = !DILocation(line: 13, column: 29, scope: !48)
-// CHECK:STDOUT: !53 = !DILocation(line: 13, column: 22, scope: !48)
-// CHECK:STDOUT: !54 = distinct !DISubprogram(name: "GetI64", linkageName: "_CGetI64.Main", scope: null, file: !7, line: 14, type: !55, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !55 = !DISubroutineType(types: !56)
-// CHECK:STDOUT: !56 = !{!57}
-// CHECK:STDOUT: !57 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !58 = !DILocation(line: 14, column: 29, scope: !54)
-// CHECK:STDOUT: !59 = !DILocation(line: 14, column: 22, scope: !54)
-// CHECK:STDOUT: !60 = distinct !DISubprogram(name: "Lets", linkageName: "_CLets.Main", scope: null, file: !7, line: 18, type: !61, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !61 = !DISubroutineType(types: !62)
-// CHECK:STDOUT: !62 = !{null}
-// CHECK:STDOUT: !63 = !DILocation(line: 19, column: 19, scope: !60)
-// CHECK:STDOUT: !64 = !DILocation(line: 20, column: 21, scope: !60)
-// CHECK:STDOUT: !65 = !DILocation(line: 24, column: 19, scope: !60)
-// CHECK:STDOUT: !66 = !DILocation(line: 25, column: 21, scope: !60)
-// CHECK:STDOUT: !67 = !DILocation(line: 21, column: 21, scope: !60)
-// CHECK:STDOUT: !68 = !DILocation(line: 22, column: 21, scope: !60)
-// CHECK:STDOUT: !69 = !DILocation(line: 26, column: 21, scope: !60)
-// CHECK:STDOUT: !70 = !DILocation(line: 27, column: 21, scope: !60)
-// CHECK:STDOUT: !71 = !DILocation(line: 29, column: 3, scope: !60)
-// CHECK:STDOUT: !72 = !DILocation(line: 18, column: 1, scope: !60)
-// CHECK:STDOUT: !73 = distinct !DISubprogram(name: "Vars", linkageName: "_CVars.Main", scope: null, file: !7, line: 32, type: !61, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !74 = !DILocation(line: 33, column: 3, scope: !73)
-// CHECK:STDOUT: !75 = !DILocation(line: 33, column: 19, scope: !73)
-// CHECK:STDOUT: !76 = !DILocation(line: 34, column: 3, scope: !73)
-// CHECK:STDOUT: !77 = !DILocation(line: 34, column: 21, scope: !73)
-// CHECK:STDOUT: !78 = !DILocation(line: 35, column: 3, scope: !73)
-// CHECK:STDOUT: !79 = !DILocation(line: 36, column: 3, scope: !73)
-// CHECK:STDOUT: !80 = !DILocation(line: 38, column: 3, scope: !73)
-// CHECK:STDOUT: !81 = !DILocation(line: 38, column: 19, scope: !73)
-// CHECK:STDOUT: !82 = !DILocation(line: 39, column: 3, scope: !73)
-// CHECK:STDOUT: !83 = !DILocation(line: 39, column: 21, scope: !73)
-// CHECK:STDOUT: !84 = !DILocation(line: 40, column: 3, scope: !73)
-// CHECK:STDOUT: !85 = !DILocation(line: 41, column: 3, scope: !73)
-// CHECK:STDOUT: !86 = !DILocation(line: 35, column: 21, scope: !73)
-// CHECK:STDOUT: !87 = !DILocation(line: 36, column: 21, scope: !73)
-// CHECK:STDOUT: !88 = !DILocation(line: 40, column: 21, scope: !73)
-// CHECK:STDOUT: !89 = !DILocation(line: 41, column: 21, scope: !73)
-// CHECK:STDOUT: !90 = !DILocation(line: 43, column: 7, scope: !73)
-// CHECK:STDOUT: !91 = !DILocation(line: 43, column: 14, scope: !73)
-// CHECK:STDOUT: !92 = !DILocation(line: 43, column: 22, scope: !73)
-// CHECK:STDOUT: !93 = !DILocation(line: 43, column: 30, scope: !73)
-// CHECK:STDOUT: !94 = !DILocation(line: 43, column: 38, scope: !73)
-// CHECK:STDOUT: !95 = !DILocation(line: 43, column: 45, scope: !73)
-// CHECK:STDOUT: !96 = !DILocation(line: 43, column: 53, scope: !73)
-// CHECK:STDOUT: !97 = !DILocation(line: 43, column: 61, scope: !73)
-// CHECK:STDOUT: !98 = !DILocation(line: 43, column: 3, scope: !73)
-// CHECK:STDOUT: !99 = !DILocation(line: 32, column: 1, scope: !73)
-// CHECK:STDOUT: !100 = !{!101, !101, i64 0}
-// CHECK:STDOUT: !101 = !{!"p1 omnipotent char", !102, i64 0}
-// CHECK:STDOUT: !102 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !103 = !{!10, !10, i64 0}
-// CHECK:STDOUT: !104 = !{!105, !105, i64 0}
-// CHECK:STDOUT: !105 = !{!"p1 short", !102, i64 0}
-// CHECK:STDOUT: !106 = !{!107, !107, i64 0}
-// CHECK:STDOUT: !107 = !{!"short", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 omnipotent char", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!10, !10, i64 0}
+// CHECK:STDOUT: !16 = !{!17, !17, i64 0}
+// CHECK:STDOUT: !17 = !{!"p1 short", !14, i64 0}
+// CHECK:STDOUT: !18 = !{!19, !19, i64 0}
+// CHECK:STDOUT: !19 = !{!"short", !10, i64 0}
+// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "GetU8", linkageName: "_CGetU8.Main", scope: null, file: !7, line: 6, type: !21, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
+// CHECK:STDOUT: !22 = !{!23}
+// CHECK:STDOUT: !23 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !24 = !DILocation(line: 6, column: 27, scope: !20)
+// CHECK:STDOUT: !25 = !DILocation(line: 6, column: 20, scope: !20)
+// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "GetU16", linkageName: "_CGetU16.Main", scope: null, file: !7, line: 7, type: !27, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !27 = !DISubroutineType(types: !28)
+// CHECK:STDOUT: !28 = !{!29}
+// CHECK:STDOUT: !29 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !30 = !DILocation(line: 7, column: 29, scope: !26)
+// CHECK:STDOUT: !31 = !DILocation(line: 7, column: 22, scope: !26)
+// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "GetU32", linkageName: "_CGetU32.Main", scope: null, file: !7, line: 8, type: !33, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !33 = !DISubroutineType(types: !34)
+// CHECK:STDOUT: !34 = !{!35}
+// CHECK:STDOUT: !35 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !36 = !DILocation(line: 8, column: 29, scope: !32)
+// CHECK:STDOUT: !37 = !DILocation(line: 8, column: 22, scope: !32)
+// CHECK:STDOUT: !38 = distinct !DISubprogram(name: "GetU64", linkageName: "_CGetU64.Main", scope: null, file: !7, line: 9, type: !39, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !39 = !DISubroutineType(types: !40)
+// CHECK:STDOUT: !40 = !{!41}
+// CHECK:STDOUT: !41 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_unsigned)
+// CHECK:STDOUT: !42 = !DILocation(line: 9, column: 29, scope: !38)
+// CHECK:STDOUT: !43 = !DILocation(line: 9, column: 22, scope: !38)
+// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "GetI8", linkageName: "_CGetI8.Main", scope: null, file: !7, line: 11, type: !45, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !45 = !DISubroutineType(types: !46)
+// CHECK:STDOUT: !46 = !{!47}
+// CHECK:STDOUT: !47 = !DIBasicType(name: "int", size: 8, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !48 = !DILocation(line: 11, column: 27, scope: !44)
+// CHECK:STDOUT: !49 = !DILocation(line: 11, column: 20, scope: !44)
+// CHECK:STDOUT: !50 = distinct !DISubprogram(name: "GetI16", linkageName: "_CGetI16.Main", scope: null, file: !7, line: 12, type: !51, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !51 = !DISubroutineType(types: !52)
+// CHECK:STDOUT: !52 = !{!53}
+// CHECK:STDOUT: !53 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !54 = !DILocation(line: 12, column: 29, scope: !50)
+// CHECK:STDOUT: !55 = !DILocation(line: 12, column: 22, scope: !50)
+// CHECK:STDOUT: !56 = distinct !DISubprogram(name: "GetI32", linkageName: "_CGetI32.Main", scope: null, file: !7, line: 13, type: !57, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !57 = !DISubroutineType(types: !58)
+// CHECK:STDOUT: !58 = !{!59}
+// CHECK:STDOUT: !59 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !60 = !DILocation(line: 13, column: 29, scope: !56)
+// CHECK:STDOUT: !61 = !DILocation(line: 13, column: 22, scope: !56)
+// CHECK:STDOUT: !62 = distinct !DISubprogram(name: "GetI64", linkageName: "_CGetI64.Main", scope: null, file: !7, line: 14, type: !63, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !63 = !DISubroutineType(types: !64)
+// CHECK:STDOUT: !64 = !{!65}
+// CHECK:STDOUT: !65 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !66 = !DILocation(line: 14, column: 29, scope: !62)
+// CHECK:STDOUT: !67 = !DILocation(line: 14, column: 22, scope: !62)
+// CHECK:STDOUT: !68 = distinct !DISubprogram(name: "Lets", linkageName: "_CLets.Main", scope: null, file: !7, line: 18, type: !69, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !69 = !DISubroutineType(types: !70)
+// CHECK:STDOUT: !70 = !{null}
+// CHECK:STDOUT: !71 = !DILocation(line: 19, column: 19, scope: !68)
+// CHECK:STDOUT: !72 = !DILocation(line: 20, column: 21, scope: !68)
+// CHECK:STDOUT: !73 = !DILocation(line: 24, column: 19, scope: !68)
+// CHECK:STDOUT: !74 = !DILocation(line: 25, column: 21, scope: !68)
+// CHECK:STDOUT: !75 = !DILocation(line: 21, column: 21, scope: !68)
+// CHECK:STDOUT: !76 = !DILocation(line: 22, column: 21, scope: !68)
+// CHECK:STDOUT: !77 = !DILocation(line: 26, column: 21, scope: !68)
+// CHECK:STDOUT: !78 = !DILocation(line: 27, column: 21, scope: !68)
+// CHECK:STDOUT: !79 = !DILocation(line: 29, column: 3, scope: !68)
+// CHECK:STDOUT: !80 = !DILocation(line: 18, column: 1, scope: !68)
+// CHECK:STDOUT: !81 = distinct !DISubprogram(name: "Vars", linkageName: "_CVars.Main", scope: null, file: !7, line: 32, type: !69, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !82 = !DILocation(line: 33, column: 3, scope: !81)
+// CHECK:STDOUT: !83 = !DILocation(line: 33, column: 19, scope: !81)
+// CHECK:STDOUT: !84 = !DILocation(line: 34, column: 3, scope: !81)
+// CHECK:STDOUT: !85 = !DILocation(line: 34, column: 21, scope: !81)
+// CHECK:STDOUT: !86 = !DILocation(line: 35, column: 3, scope: !81)
+// CHECK:STDOUT: !87 = !DILocation(line: 36, column: 3, scope: !81)
+// CHECK:STDOUT: !88 = !DILocation(line: 38, column: 3, scope: !81)
+// CHECK:STDOUT: !89 = !DILocation(line: 38, column: 19, scope: !81)
+// CHECK:STDOUT: !90 = !DILocation(line: 39, column: 3, scope: !81)
+// CHECK:STDOUT: !91 = !DILocation(line: 39, column: 21, scope: !81)
+// CHECK:STDOUT: !92 = !DILocation(line: 40, column: 3, scope: !81)
+// CHECK:STDOUT: !93 = !DILocation(line: 41, column: 3, scope: !81)
+// CHECK:STDOUT: !94 = !DILocation(line: 35, column: 21, scope: !81)
+// CHECK:STDOUT: !95 = !DILocation(line: 36, column: 21, scope: !81)
+// CHECK:STDOUT: !96 = !DILocation(line: 40, column: 21, scope: !81)
+// CHECK:STDOUT: !97 = !DILocation(line: 41, column: 21, scope: !81)
+// CHECK:STDOUT: !98 = !DILocation(line: 43, column: 7, scope: !81)
+// CHECK:STDOUT: !99 = !DILocation(line: 43, column: 14, scope: !81)
+// CHECK:STDOUT: !100 = !DILocation(line: 43, column: 22, scope: !81)
+// CHECK:STDOUT: !101 = !DILocation(line: 43, column: 30, scope: !81)
+// CHECK:STDOUT: !102 = !DILocation(line: 43, column: 38, scope: !81)
+// CHECK:STDOUT: !103 = !DILocation(line: 43, column: 45, scope: !81)
+// CHECK:STDOUT: !104 = !DILocation(line: 43, column: 53, scope: !81)
+// CHECK:STDOUT: !105 = !DILocation(line: 43, column: 61, scope: !81)
+// CHECK:STDOUT: !106 = !DILocation(line: 43, column: 3, scope: !81)
+// CHECK:STDOUT: !107 = !DILocation(line: 32, column: 1, scope: !81)
 // CHECK:STDOUT: ; ModuleID = 'import_class.carbon'
 // CHECK:STDOUT: source_filename = "import_class.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -463,57 +463,59 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT:
 // CHECK:STDOUT: %struct.X = type { ptr, ptr }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CGetX.Main(ptr sret([16 x i8]) %return) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %return), !dbg !16
-// CHECK:STDOUT:   ret void, !dbg !17
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CLet.Main() #0 !dbg !18 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc9_27.1.temp = alloca [16 x i8], align 1, !dbg !21
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_27.1.temp), !dbg !21
-// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %.loc9_27.1.temp), !dbg !21
-// CHECK:STDOUT:   call void @_ZN1XD1Ev(ptr %.loc9_27.1.temp), !dbg !21
-// CHECK:STDOUT:   ret void, !dbg !22
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_ZN1XD1Ev(ptr)
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CVar.Main() #0 !dbg !23 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %_.var = alloca [16 x i8], align 1, !dbg !24
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var), !dbg !24
-// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %_.var), !dbg !25
-// CHECK:STDOUT:   call void @_ZN1XD1Ev(ptr %_.var), !dbg !24
-// CHECK:STDOUT:   ret void, !dbg !26
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z4Makev.carbon_thunk(ptr noundef %return) #2 {
+// CHECK:STDOUT: define dso_local void @_Z4Makev.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z4Makev(ptr dead_on_unwind writable sret(%struct.X) align 8 %0)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z4Makev(ptr dead_on_unwind writable sret(%struct.X) align 8) #3
+// CHECK:STDOUT: declare void @_Z4Makev(ptr dead_on_unwind writable sret(%struct.X) align 8) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CGetX.Main(ptr sret([16 x i8]) %return) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %return), !dbg !19
+// CHECK:STDOUT:   ret void, !dbg !20
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CLet.Main() #2 !dbg !21 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc9_27.1.temp = alloca [16 x i8], align 1, !dbg !24
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc9_27.1.temp), !dbg !24
+// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %.loc9_27.1.temp), !dbg !24
+// CHECK:STDOUT:   call void @_ZN1XD1Ev(ptr %.loc9_27.1.temp), !dbg !24
+// CHECK:STDOUT:   ret void, !dbg !25
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: declare void @_ZN1XD1Ev(ptr noundef nonnull align 8 dereferenceable(16)) unnamed_addr #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CVar.Main() #2 !dbg !26 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %_.var = alloca [16 x i8], align 1, !dbg !27
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var), !dbg !27
+// CHECK:STDOUT:   call void @_Z4Makev.carbon_thunk(ptr %_.var), !dbg !28
+// CHECK:STDOUT:   call void @_ZN1XD1Ev(ptr %_.var), !dbg !27
+// CHECK:STDOUT:   ret void, !dbg !29
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -522,7 +524,7 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -531,58 +533,59 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "GetX", linkageName: "_CGetX.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 29, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 6, column: 22, scope: !12)
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "Let", linkageName: "_CLet.Main", scope: null, file: !7, line: 8, type: !19, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
-// CHECK:STDOUT: !20 = !{null}
-// CHECK:STDOUT: !21 = !DILocation(line: 9, column: 18, scope: !18)
-// CHECK:STDOUT: !22 = !DILocation(line: 8, column: 1, scope: !18)
-// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "Var", linkageName: "_CVar.Main", scope: null, file: !7, line: 12, type: !19, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !24 = !DILocation(line: 13, column: 3, scope: !23)
-// CHECK:STDOUT: !25 = !DILocation(line: 13, column: 18, scope: !23)
-// CHECK:STDOUT: !26 = !DILocation(line: 12, column: 1, scope: !23)
-// CHECK:STDOUT: !27 = !{!28, !28, i64 0}
-// CHECK:STDOUT: !28 = !{!"p1 _ZTS1X", !29, i64 0}
-// CHECK:STDOUT: !29 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1X", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "GetX", linkageName: "_CGetX.Main", scope: null, file: !7, line: 6, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !19 = !DILocation(line: 6, column: 29, scope: !15)
+// CHECK:STDOUT: !20 = !DILocation(line: 6, column: 22, scope: !15)
+// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "Let", linkageName: "_CLet.Main", scope: null, file: !7, line: 8, type: !22, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !22 = !DISubroutineType(types: !23)
+// CHECK:STDOUT: !23 = !{null}
+// CHECK:STDOUT: !24 = !DILocation(line: 9, column: 18, scope: !21)
+// CHECK:STDOUT: !25 = !DILocation(line: 8, column: 1, scope: !21)
+// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "Var", linkageName: "_CVar.Main", scope: null, file: !7, line: 12, type: !22, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !27 = !DILocation(line: 13, column: 3, scope: !26)
+// CHECK:STDOUT: !28 = !DILocation(line: 13, column: 18, scope: !26)
+// CHECK:STDOUT: !29 = !DILocation(line: 12, column: 1, scope: !26)
 // CHECK:STDOUT: ; ModuleID = 'indirect_return_with_args.carbon'
 // CHECK:STDOUT: source_filename = "indirect_return_with_args.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
 // CHECK:STDOUT: %class.D = type { i8 }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCall.Main(ptr sret({}) %return, ptr %x) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z1f1D.carbon_thunk(ptr %x, ptr %return), !dbg !18
-// CHECK:STDOUT:   ret void, !dbg !19
-// CHECK:STDOUT: }
+// CHECK:STDOUT: %class.C = type { i8 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z1f1D.carbon_thunk(ptr noundef %0, ptr noundef %return) #1 {
+// CHECK:STDOUT: define dso_local void @_Z1f1D.carbon_thunk(ptr noundef %0, ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.D, align 1
-// CHECK:STDOUT:   %undef.agg.tmp = alloca %class.D, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !20
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !23
-// CHECK:STDOUT:   %1 = load ptr, ptr %return.addr, align 8, !tbaa !23
-// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !20
+// CHECK:STDOUT:   %undef.agg.tmp = alloca %class.C, align 1
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %1 = load ptr, ptr %return.addr, align 8, !tbaa !15
+// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z1f1D()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z1f1D() #2
+// CHECK:STDOUT: declare void @_Z1f1D() #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCall.Main(ptr sret({}) %return, ptr %x) #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z1f1D.carbon_thunk(ptr %x, ptr %return), !dbg !23
+// CHECK:STDOUT:   ret void, !dbg !24
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -591,7 +594,7 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -600,16 +603,16 @@ fn Call(x: Cpp.D) -> Cpp.C {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 10, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15, !15}
-// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 11, column: 10, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 11, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = !{!21, !21, i64 0}
-// CHECK:STDOUT: !21 = !{!"p1 _ZTS1D", !22, i64 0}
-// CHECK:STDOUT: !22 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !23 = !{!24, !24, i64 0}
-// CHECK:STDOUT: !24 = !{!"p1 _ZTS1C", !22, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1D", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"p1 _ZTS1C", !14, i64 0}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "Call", linkageName: "_CCall.Main", scope: null, file: !7, line: 10, type: !18, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !21)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{!20, !20}
+// CHECK:STDOUT: !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !21 = !{!22}
+// CHECK:STDOUT: !22 = !DILocalVariable(arg: 1, scope: !17, type: !20)
+// CHECK:STDOUT: !23 = !DILocation(line: 11, column: 10, scope: !17)
+// CHECK:STDOUT: !24 = !DILocation(line: 11, column: 3, scope: !17)
diff --git a/toolchain/lower/testdata/interop/cpp/template.carbon b/toolchain/lower/testdata/interop/cpp/template.carbon
index 7345f40f3ef5..d5b5d4284bb3 100644
--- a/toolchain/lower/testdata/interop/cpp/template.carbon
+++ b/toolchain/lower/testdata/interop/cpp/template.carbon
@@ -96,44 +96,37 @@ fn Call3() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_Z8identityIiET_S0_ = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CPassI32.Main(i32 %a) #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %identity.call = call i32 @_Z8identityIiET_S0_(i32 %a), !dbg !18
-// CHECK:STDOUT:   ret i32 %identity.call, !dbg !19
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CPassClass.Main(ptr sret({}) %return, ptr %a) #0 !dbg !20 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z8identityI5ClassET_S1_.carbon_thunk(ptr %a, ptr %return), !dbg !26
-// CHECK:STDOUT:   ret void, !dbg !27
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z8identityI5ClassET_S1_.carbon_thunk(ptr noundef %x, ptr noundef %return) #1 {
+// CHECK:STDOUT: define dso_local void @_Z8identityI5ClassET_S1_.carbon_thunk(ptr noundef %x, ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %x.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.Class, align 1
 // CHECK:STDOUT:   %undef.agg.tmp = alloca %class.Class, align 1
-// CHECK:STDOUT:   store ptr %x, ptr %x.addr, align 8, !tbaa !28
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !28
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !28
-// CHECK:STDOUT:   %1 = load ptr, ptr %x.addr, align 8, !tbaa !28
+// CHECK:STDOUT:   store ptr %x, ptr %x.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %x.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z8identityI5ClassET_S1_()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_Z8identityI5ClassET_S1_() #2 comdat {
+// CHECK:STDOUT: define linkonce_odr dso_local void @_Z8identityI5ClassET_S1_() #1 comdat {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %x = alloca %class.Class, align 1
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CPassI32.Main(i32 %a) #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %identity.call = call i32 @_Z8identityIiET_S0_(i32 %a), !dbg !21
+// CHECK:STDOUT:   ret i32 %identity.call, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_Z8identityIiET_S0_(i32 noundef %x) #2 comdat {
+// CHECK:STDOUT: define linkonce_odr dso_local noundef i32 @_Z8identityIiET_S0_(i32 noundef %x) #1 comdat {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %x.addr = alloca i32, align 4
 // CHECK:STDOUT:   store i32 %x, ptr %x.addr, align 4, !tbaa !8
@@ -141,9 +134,16 @@ fn Call3() {
 // CHECK:STDOUT:   ret i32 %0
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #2 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CPassClass.Main(ptr sret({}) %return, ptr %a) #2 !dbg !23 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z8identityI5ClassET_S1_.carbon_thunk(ptr %a, ptr %return), !dbg !29
+// CHECK:STDOUT:   ret void, !dbg !30
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -152,7 +152,7 @@ fn Call3() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -161,25 +161,25 @@ fn Call3() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "PassI32", linkageName: "_CPassI32.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !16)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{!15, !15}
-// CHECK:STDOUT: !15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !16 = !{!17}
-// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !12, type: !15)
-// CHECK:STDOUT: !18 = !DILocation(line: 7, column: 10, scope: !12)
-// CHECK:STDOUT: !19 = !DILocation(line: 7, column: 3, scope: !12)
-// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "PassClass", linkageName: "_CPassClass.Main", scope: null, file: !7, line: 10, type: !21, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !24)
-// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
-// CHECK:STDOUT: !22 = !{!23, !23}
-// CHECK:STDOUT: !23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !24 = !{!25}
-// CHECK:STDOUT: !25 = !DILocalVariable(arg: 1, scope: !20, type: !23)
-// CHECK:STDOUT: !26 = !DILocation(line: 11, column: 10, scope: !20)
-// CHECK:STDOUT: !27 = !DILocation(line: 11, column: 3, scope: !20)
-// CHECK:STDOUT: !28 = !{!29, !29, i64 0}
-// CHECK:STDOUT: !29 = !{!"p1 _ZTS5Class", !30, i64 0}
-// CHECK:STDOUT: !30 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS5Class", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "PassI32", linkageName: "_CPassI32.Main", scope: null, file: !7, line: 6, type: !16, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{!18, !18}
+// CHECK:STDOUT: !18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !19 = !{!20}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocation(line: 7, column: 10, scope: !15)
+// CHECK:STDOUT: !22 = !DILocation(line: 7, column: 3, scope: !15)
+// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "PassClass", linkageName: "_CPassClass.Main", scope: null, file: !7, line: 10, type: !24, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !27)
+// CHECK:STDOUT: !24 = !DISubroutineType(types: !25)
+// CHECK:STDOUT: !25 = !{!26, !26}
+// CHECK:STDOUT: !26 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !27 = !{!28}
+// CHECK:STDOUT: !28 = !DILocalVariable(arg: 1, scope: !23, type: !26)
+// CHECK:STDOUT: !29 = !DILocation(line: 11, column: 10, scope: !23)
+// CHECK:STDOUT: !30 = !DILocation(line: 11, column: 3, scope: !23)
 // CHECK:STDOUT: ; ModuleID = 'variadic.carbon'
 // CHECK:STDOUT: source_filename = "variadic.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -192,7 +192,7 @@ fn Call3() {
 // CHECK:STDOUT:   ret void, !dbg !16
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJEEviDpT_(i32)
+// CHECK:STDOUT: declare void @_Z3fooIJEEviDpT_(i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define void @_CCall2.Main() #0 !dbg !17 {
@@ -201,7 +201,7 @@ fn Call3() {
 // CHECK:STDOUT:   ret void, !dbg !19
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJiEEviDpT_(i32, i32)
+// CHECK:STDOUT: declare void @_Z3fooIJiEEviDpT_(i32 noundef, i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define void @_CCall3.Main() #0 !dbg !20 {
@@ -210,9 +210,10 @@ fn Call3() {
 // CHECK:STDOUT:   ret void, !dbg !22
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJiiEEviDpT_(i32, i32, i32)
+// CHECK:STDOUT: declare void @_Z3fooIJiiEEviDpT_(i32 noundef, i32 noundef, i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -221,7 +222,7 @@ fn Call3() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -250,99 +251,99 @@ fn Call3() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: @X.val.loc12_12.3 = internal constant {} zeroinitializer
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCall1.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc12_12.2.temp = alloca {}, align 8, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_12.2.temp), !dbg !15
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc12_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !15
-// CHECK:STDOUT:   call void @_Z3fooIJEEv1XDpT_.carbon_thunk(ptr %.loc12_12.2.temp), !dbg !16
-// CHECK:STDOUT:   ret void, !dbg !17
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCall2.Main() #0 !dbg !18 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc18_12.2.temp = alloca {}, align 8, !dbg !19
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc18_12.2.temp), !dbg !19
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc18_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !19
-// CHECK:STDOUT:   call void @_Z3fooIJiEEv1XDpT_.carbon_thunk(ptr %.loc18_12.2.temp, i32 2), !dbg !20
-// CHECK:STDOUT:   ret void, !dbg !21
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCall3.Main() #0 !dbg !22 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc24_12.2.temp = alloca {}, align 8, !dbg !23
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_12.2.temp), !dbg !23
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc24_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !23
-// CHECK:STDOUT:   call void @_Z3fooIJiiEEv1XDpT_.carbon_thunk(ptr %.loc24_12.2.temp, i32 2, i32 3), !dbg !24
-// CHECK:STDOUT:   ret void, !dbg !25
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #2
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z3fooIJEEv1XDpT_.carbon_thunk(ptr noundef %0) #3 {
+// CHECK:STDOUT: define dso_local void @_Z3fooIJEEv1XDpT_.carbon_thunk(ptr noundef %0) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %agg.tmp = alloca %class.X, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !26
-// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !26
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %1 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_Z3fooIJEEv1XDpT_()
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJEEv1XDpT_() #4
+// CHECK:STDOUT: declare void @_Z3fooIJEEv1XDpT_() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z3fooIJiEEv1XDpT_.carbon_thunk(ptr noundef %0, i32 noundef %1) #3 {
+// CHECK:STDOUT: define dso_local void @_Z3fooIJiEEv1XDpT_.carbon_thunk(ptr noundef %0, i32 noundef %1) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %.addr1 = alloca i32, align 4
 // CHECK:STDOUT:   %agg.tmp = alloca %class.X, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !26
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   store i32 %1, ptr %.addr1, align 4, !tbaa !8
-// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !26
+// CHECK:STDOUT:   %2 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %3 = load i32, ptr %.addr1, align 4, !tbaa !8
 // CHECK:STDOUT:   call void @_Z3fooIJiEEv1XDpT_(i32 noundef %3)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJiEEv1XDpT_(i32 noundef) #4
+// CHECK:STDOUT: declare void @_Z3fooIJiEEv1XDpT_(i32 noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_Z3fooIJiiEEv1XDpT_.carbon_thunk(ptr noundef %0, i32 noundef %1, i32 noundef %2) #3 {
+// CHECK:STDOUT: define dso_local void @_Z3fooIJiiEEv1XDpT_.carbon_thunk(ptr noundef %0, i32 noundef %1, i32 noundef %2) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %.addr = alloca ptr, align 8
 // CHECK:STDOUT:   %.addr1 = alloca i32, align 4
 // CHECK:STDOUT:   %.addr2 = alloca i32, align 4
 // CHECK:STDOUT:   %agg.tmp = alloca %class.X, align 1
-// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !26
+// CHECK:STDOUT:   store ptr %0, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   store i32 %1, ptr %.addr1, align 4, !tbaa !8
 // CHECK:STDOUT:   store i32 %2, ptr %.addr2, align 4, !tbaa !8
-// CHECK:STDOUT:   %3 = load ptr, ptr %.addr, align 8, !tbaa !26
+// CHECK:STDOUT:   %3 = load ptr, ptr %.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %4 = load i32, ptr %.addr1, align 4, !tbaa !8
 // CHECK:STDOUT:   %5 = load i32, ptr %.addr2, align 4, !tbaa !8
 // CHECK:STDOUT:   call void @_Z3fooIJiiEEv1XDpT_(i32 noundef %4, i32 noundef %5)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z3fooIJiiEEv1XDpT_(i32 noundef, i32 noundef) #4
+// CHECK:STDOUT: declare void @_Z3fooIJiiEEv1XDpT_(i32 noundef, i32 noundef) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCall1.Main() #2 !dbg !15 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc12_12.2.temp = alloca {}, align 8, !dbg !18
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc12_12.2.temp), !dbg !18
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc12_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !18
+// CHECK:STDOUT:   call void @_Z3fooIJEEv1XDpT_.carbon_thunk(ptr %.loc12_12.2.temp), !dbg !19
+// CHECK:STDOUT:   ret void, !dbg !20
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCall2.Main() #2 !dbg !21 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc18_12.2.temp = alloca {}, align 8, !dbg !22
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc18_12.2.temp), !dbg !22
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc18_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !22
+// CHECK:STDOUT:   call void @_Z3fooIJiEEv1XDpT_.carbon_thunk(ptr %.loc18_12.2.temp, i32 2), !dbg !23
+// CHECK:STDOUT:   ret void, !dbg !24
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCall3.Main() #2 !dbg !25 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc24_12.2.temp = alloca {}, align 8, !dbg !26
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %.loc24_12.2.temp), !dbg !26
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc24_12.2.temp, ptr align 1 @X.val.loc12_12.3, i64 0, i1 false), !dbg !26
+// CHECK:STDOUT:   call void @_Z3fooIJiiEEv1XDpT_.carbon_thunk(ptr %.loc24_12.2.temp, i32 2, i32 3), !dbg !27
+// CHECK:STDOUT:   ret void, !dbg !28
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 2, 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 2, 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -351,7 +352,7 @@ fn Call3() {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -360,20 +361,20 @@ fn Call3() {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Call1", linkageName: "_CCall1.Main", scope: null, file: !7, line: 10, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 12, column: 11, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 12, column: 3, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 10, column: 1, scope: !12)
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "Call2", linkageName: "_CCall2.Main", scope: null, file: !7, line: 16, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !19 = !DILocation(line: 18, column: 11, scope: !18)
-// CHECK:STDOUT: !20 = !DILocation(line: 18, column: 3, scope: !18)
-// CHECK:STDOUT: !21 = !DILocation(line: 16, column: 1, scope: !18)
-// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "Call3", linkageName: "_CCall3.Main", scope: null, file: !7, line: 22, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !23 = !DILocation(line: 24, column: 11, scope: !22)
-// CHECK:STDOUT: !24 = !DILocation(line: 24, column: 3, scope: !22)
-// CHECK:STDOUT: !25 = !DILocation(line: 22, column: 1, scope: !22)
-// CHECK:STDOUT: !26 = !{!27, !27, i64 0}
-// CHECK:STDOUT: !27 = !{!"p1 _ZTS1X", !28, i64 0}
-// CHECK:STDOUT: !28 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1X", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "Call1", linkageName: "_CCall1.Main", scope: null, file: !7, line: 10, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{null}
+// CHECK:STDOUT: !18 = !DILocation(line: 12, column: 11, scope: !15)
+// CHECK:STDOUT: !19 = !DILocation(line: 12, column: 3, scope: !15)
+// CHECK:STDOUT: !20 = !DILocation(line: 10, column: 1, scope: !15)
+// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "Call2", linkageName: "_CCall2.Main", scope: null, file: !7, line: 16, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !22 = !DILocation(line: 18, column: 11, scope: !21)
+// CHECK:STDOUT: !23 = !DILocation(line: 18, column: 3, scope: !21)
+// CHECK:STDOUT: !24 = !DILocation(line: 16, column: 1, scope: !21)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Call3", linkageName: "_CCall3.Main", scope: null, file: !7, line: 22, type: !16, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !26 = !DILocation(line: 24, column: 11, scope: !25)
+// CHECK:STDOUT: !27 = !DILocation(line: 24, column: 3, scope: !25)
+// CHECK:STDOUT: !28 = !DILocation(line: 22, column: 1, scope: !25)
diff --git a/toolchain/lower/testdata/interop/cpp/virtual_base.carbon b/toolchain/lower/testdata/interop/cpp/virtual_base.carbon
index af8efc7edd80..8a18b9a9f921 100644
--- a/toolchain/lower/testdata/interop/cpp/virtual_base.carbon
+++ b/toolchain/lower/testdata/interop/cpp/virtual_base.carbon
@@ -108,53 +108,53 @@ fn AccessD(d: Cpp.D) -> i32 {
 // CHECK:STDOUT: @_ZTI1D = linkonce_odr dso_local constant { ptr, ptr, i32, i32, ptr, i64, ptr, i64 } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv121__vmi_class_type_infoE, i64 2), ptr @_ZTS1D, i32 2, i32 2, ptr @_ZTI1B, i64 2, ptr @_ZTI1C, i64 4098 }, comdat, align 8
 // CHECK:STDOUT: @_ZTS1D = linkonce_odr dso_local constant [3 x i8] c"1D\00", comdat, align 1
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CMake.Main() #0 !dbg !12 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %_.var = alloca [40 x i8], align 1, !dbg !15
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var), !dbg !15
-// CHECK:STDOUT:   call void @_ZN1DC1Ev.carbon_thunk(ptr %_.var), !dbg !16
-// CHECK:STDOUT:   ret void, !dbg !17
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CAccessD.Main(ptr %d) #0 !dbg !18 {
-// CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc16_11.1.d = getelementptr inbounds nuw [40 x i8], ptr %d, i32 0, i32 28, !dbg !25
-// CHECK:STDOUT:   %.loc16_11.2 = load i32, ptr %.loc16_11.1.d, align 4, !dbg !25
-// CHECK:STDOUT:   ret i32 %.loc16_11.2, !dbg !26
-// CHECK:STDOUT: }
-// CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
-// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress uwtable
-// CHECK:STDOUT: define dso_local void @_ZN1DC1Ev.carbon_thunk(ptr noundef %return) #2 {
+// CHECK:STDOUT: define dso_local void @_ZN1DC1Ev.carbon_thunk(ptr noundef %return) #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %return.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !27
-// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %return, ptr %return.addr, align 8, !tbaa !12
+// CHECK:STDOUT:   %0 = load ptr, ptr %return.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   call void @_ZN1DC1Ev(ptr noundef nonnull align 8 dereferenceable(32) %0)
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress uwtable
-// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1DC1Ev(ptr noundef nonnull align 8 dereferenceable(32) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1DC1Ev(ptr noundef nonnull align 8 dereferenceable(32) %this) unnamed_addr #1 comdat align 2 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
-// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !27
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !12
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
 // CHECK:STDOUT:   %0 = getelementptr inbounds i8, ptr %this1, i64 32
 // CHECK:STDOUT:   call void @_ZN1AC2Ev(ptr noundef nonnull align 4 dereferenceable(4) %0)
 // CHECK:STDOUT:   call void @_ZN1BC2Ev(ptr noundef nonnull align 8 dereferenceable(12) %this1, ptr noundef getelementptr inbounds ([4 x ptr], ptr @_ZTT1D, i64 0, i64 1))
 // CHECK:STDOUT:   %1 = getelementptr inbounds i8, ptr %this1, i64 16
 // CHECK:STDOUT:   call void @_ZN1CC2Ev(ptr noundef nonnull align 8 dereferenceable(12) %1, ptr noundef getelementptr inbounds ([4 x ptr], ptr @_ZTT1D, i64 0, i64 2))
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 0, i32 3), ptr %this1, align 8, !tbaa !30
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 0, i32 3), ptr %this1, align 8, !tbaa !15
 // CHECK:STDOUT:   %add.ptr = getelementptr inbounds i8, ptr %this1, i64 16
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 1, i32 3), ptr %add.ptr, align 8, !tbaa !30
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 1, i32 3), ptr %add.ptr, align 8, !tbaa !15
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CMake.Main() #2 !dbg !17 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %_.var = alloca [40 x i8], align 1, !dbg !20
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %_.var), !dbg !20
+// CHECK:STDOUT:   call void @_ZN1DC1Ev.carbon_thunk(ptr %_.var), !dbg !21
+// CHECK:STDOUT:   ret void, !dbg !22
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CAccessD.Main(ptr %d) #2 !dbg !23 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc16_11.1.d = getelementptr inbounds nuw [40 x i8], ptr %d, i32 0, i32 28, !dbg !30
+// CHECK:STDOUT:   %.loc16_11.2 = load i32, ptr %.loc16_11.1.d, align 4, !dbg !30
+// CHECK:STDOUT:   ret i32 %.loc16_11.2, !dbg !31
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
+// CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_ZN1AC2Ev(ptr noundef nonnull align 4 dereferenceable(4)) unnamed_addr #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_ZN1BC2Ev(ptr noundef nonnull align 8 dereferenceable(12), ptr noundef) unnamed_addr #4
@@ -162,18 +162,16 @@ fn AccessD(d: Cpp.D) -> i32 {
 // CHECK:STDOUT: declare void @_ZN1CC2Ev(ptr noundef nonnull align 8 dereferenceable(12), ptr noundef) unnamed_addr #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
+// CHECK:STDOUT: uselistorder ptr inttoptr (i64 32 to ptr), { 1, 0 }
+// CHECK:STDOUT: uselistorder ptr inttoptr (i64 16 to ptr), { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 0, i32 3), { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr getelementptr inbounds inrange(-24, 0) ({ [3 x ptr], [3 x ptr] }, ptr @_ZTV1D, i32 0, i32 1, i32 3), { 1, 0 }
-// CHECK:STDOUT: uselistorder ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv121__vmi_class_type_infoE, i64 2), { 2, 1, 0 }
-// CHECK:STDOUT: uselistorder ptr @_ZTI1B, { 1, 0 }
-// CHECK:STDOUT: uselistorder ptr @_ZTI1A, { 1, 0 }
-// CHECK:STDOUT: uselistorder ptr @_ZTI1C, { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @_ZTI1D, { 1, 0 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { inlinehint mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #0 = { alwaysinline mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #1 = { inlinehint mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT: attributes #4 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
@@ -183,7 +181,7 @@ fn AccessD(d: Cpp.D) -> i32 {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -192,23 +190,23 @@ fn AccessD(d: Cpp.D) -> i32 {
 // CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
 // CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
 // CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
-// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "Make", linkageName: "_CMake.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
-// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
-// CHECK:STDOUT: !14 = !{null}
-// CHECK:STDOUT: !15 = !DILocation(line: 11, column: 3, scope: !12)
-// CHECK:STDOUT: !16 = !DILocation(line: 11, column: 18, scope: !12)
-// CHECK:STDOUT: !17 = !DILocation(line: 6, column: 1, scope: !12)
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "AccessD", linkageName: "_CAccessD.Main", scope: null, file: !7, line: 14, type: !19, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !23)
-// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
-// CHECK:STDOUT: !20 = !{!21, !22}
-// CHECK:STDOUT: !21 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-// CHECK:STDOUT: !22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
-// CHECK:STDOUT: !23 = !{!24}
-// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !18, type: !22)
-// CHECK:STDOUT: !25 = !DILocation(line: 16, column: 10, scope: !18)
-// CHECK:STDOUT: !26 = !DILocation(line: 16, column: 3, scope: !18)
-// CHECK:STDOUT: !27 = !{!28, !28, i64 0}
-// CHECK:STDOUT: !28 = !{!"p1 _ZTS1D", !29, i64 0}
-// CHECK:STDOUT: !29 = !{!"any pointer", !10, i64 0}
-// CHECK:STDOUT: !30 = !{!31, !31, i64 0}
-// CHECK:STDOUT: !31 = !{!"vtable pointer", !11, i64 0}
+// CHECK:STDOUT: !12 = !{!13, !13, i64 0}
+// CHECK:STDOUT: !13 = !{!"p1 _ZTS1D", !14, i64 0}
+// CHECK:STDOUT: !14 = !{!"any pointer", !10, i64 0}
+// CHECK:STDOUT: !15 = !{!16, !16, i64 0}
+// CHECK:STDOUT: !16 = !{!"vtable pointer", !11, i64 0}
+// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "Make", linkageName: "_CMake.Main", scope: null, file: !7, line: 6, type: !18, spFlags: DISPFlagDefinition, unit: !6)
+// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
+// CHECK:STDOUT: !19 = !{null}
+// CHECK:STDOUT: !20 = !DILocation(line: 11, column: 3, scope: !17)
+// CHECK:STDOUT: !21 = !DILocation(line: 11, column: 18, scope: !17)
+// CHECK:STDOUT: !22 = !DILocation(line: 6, column: 1, scope: !17)
+// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "AccessD", linkageName: "_CAccessD.Main", scope: null, file: !7, line: 14, type: !24, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !28)
+// CHECK:STDOUT: !24 = !DISubroutineType(types: !25)
+// CHECK:STDOUT: !25 = !{!26, !27}
+// CHECK:STDOUT: !26 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !27 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
+// CHECK:STDOUT: !28 = !{!29}
+// CHECK:STDOUT: !29 = !DILocalVariable(arg: 1, scope: !23, type: !27)
+// CHECK:STDOUT: !30 = !DILocation(line: 16, column: 10, scope: !23)
+// CHECK:STDOUT: !31 = !DILocation(line: 16, column: 3, scope: !23)
diff --git a/toolchain/lower/testdata/interop/cpp/void.carbon b/toolchain/lower/testdata/interop/cpp/void.carbon
index 5a6d4709f0aa..41db6ae2f6c7 100644
--- a/toolchain/lower/testdata/interop/cpp/void.carbon
+++ b/toolchain/lower/testdata/interop/cpp/void.carbon
@@ -73,7 +73,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT:   ret void, !dbg !20
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z13take_void_ptrPv(ptr)
+// CHECK:STDOUT: declare void @_Z13take_void_ptrPv(ptr noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define void @_CPassIntPtr.Main(ptr %a) #0 !dbg !21 {
@@ -99,7 +99,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare void @_Z19take_const_void_ptrPKv(ptr)
+// CHECK:STDOUT: declare void @_Z19take_const_void_ptrPKv(ptr noundef) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define void @_CPassConstIntPtrToConstVoidPtr.Main(ptr %a) #0 !dbg !33 {
@@ -120,7 +120,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #1
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #2
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define linkonce_odr ptr @"_CConvert.e5cf8fcbb4feaae2:ImplicitAs.0f95c9e18c91e00a.Core.63e244d930b21b2a"(ptr %self) #0 !dbg !47 {
@@ -168,7 +168,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert:thunk.e8f8f92d3d08d149:ImplicitAs.ffd58aeb29886b72.Core.b88d1103f417c6d4"(ptr %self) #2 !dbg !79 {
+// CHECK:STDOUT: define linkonce_odr ptr @"_CConvert:thunk.e8f8f92d3d08d149:ImplicitAs.ffd58aeb29886b72.Core.b88d1103f417c6d4"(ptr %self) #3 !dbg !79 {
 // CHECK:STDOUT:   ret ptr %self, !dbg !83
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -187,8 +187,9 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: uselistorder ptr @_CSome.Optional.Core.d2075df181ac34c1, { 2, 1, 0 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
-// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #2 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #2 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #3 = { alwaysinline nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -197,7 +198,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
@@ -297,7 +298,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT:   ret ptr %return_void_ptr.call, !dbg !17
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: declare ptr @_Z15return_void_ptrv()
+// CHECK:STDOUT: declare noundef ptr @_Z15return_void_ptrv() #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
 // CHECK:STDOUT: define ptr @_CConvertFromVoidPtr.Main(ptr %p) #0 !dbg !18 {
@@ -312,6 +313,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!6}
@@ -320,7 +322,7 @@ fn ConvertFromConstVoidPtr(p: const Cpp.void*) -> const i32* {
 // CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
 // CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
 // CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
-// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
+// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 2}
 // CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
 // CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
 // CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)