diff --git a/toolchain/check/class.cpp b/toolchain/check/class.cpp
index 17aff5d4720d..6b5756072562 100644
--- a/toolchain/check/class.cpp
+++ b/toolchain/check/class.cpp
@@ -183,12 +183,24 @@ static auto BuildVtable(Context& context, Parse::ClassDefinitionId node_id,
 
   llvm::SmallVector<SemIR::InstId> vtable;
   Set<SemIR::FunctionId> implemented_impls;
+  bool carbon_native_vtable = true;
   if (base_vtable_id.has_value()) {
-    auto base_vtable_inst_block = context.inst_blocks().Get(
-        context.vtables().Get(base_vtable_id).virtual_functions_id);
+    const auto& base_vtable = context.vtables().Get(base_vtable_id);
+    carbon_native_vtable = base_vtable.carbon_native_vtable;
+    auto base_vtable_inst_block =
+        context.inst_blocks().Get(base_vtable.virtual_functions_id);
     // TODO: Avoid quadratic search. Perhaps build a map from `NameId` to the
     // elements of the top of `vtable_stack`.
     for (auto base_vtable_entry_id : base_vtable_inst_block) {
+      if (!base_vtable_entry_id.has_value()) {
+        // Foreign vtables may have holes in them for information that we don't
+        // use. Just skip those entries.
+        CARBON_CHECK(
+            !context.vtables().Get(base_vtable_id).carbon_native_vtable);
+        vtable.push_back(SemIR::InstId::None);
+        continue;
+      }
+
       auto [derived_vtable_entry_id, derived_vtable_entry_const_id, fn_id,
             specific_id] =
           DecomposeVirtualFunction(context.sem_ir(), base_vtable_entry_id,
@@ -265,7 +277,8 @@ static auto BuildVtable(Context& context, Parse::ClassDefinitionId node_id,
 
   return context.vtables().Add(
       {{.class_id = class_id,
-        .virtual_functions_id = context.inst_blocks().Add(vtable)}});
+        .virtual_functions_id = context.inst_blocks().Add(vtable),
+        .carbon_native_vtable = carbon_native_vtable}});
 }
 
 // Checks that the specified finished class definition is valid and builds and
diff --git a/toolchain/check/cpp/import.cpp b/toolchain/check/cpp/import.cpp
index 54faacb0c1f8..c844ff5323df 100644
--- a/toolchain/check/cpp/import.cpp
+++ b/toolchain/check/cpp/import.cpp
@@ -939,25 +939,26 @@ static auto BuildClassDefinition(Context& context,
 
   if (class_info.is_dynamic) {
     llvm::SmallVector<SemIR::InstId> vtable;
-    const auto& vtable_layout = dyn_cast<clang::ItaniumVTableContext>(
-                                    context.ast_context().getVTableContext())
-                                    ->getVTableLayout(clang_def);
+    auto& vtable_context = *cast<clang::ItaniumVTableContext>(
+        context.ast_context().getVTableContext());
+    const auto& vtable_layout = vtable_context.getVTableLayout(clang_def);
     auto vtable_components = vtable_layout.vtable_components();
     vtable.reserve(vtable_components.size());
-    auto num_components = 0;
     for (const auto& vtable_component : vtable_components) {
       if (vtable_component.getKind() !=
           clang::VTableComponent::CK_FunctionPointer) {
         continue;
       }
-      ++num_components;
       const auto* method_decl = vtable_component.getFunctionDecl();
-      vtable.push_back(ImportCppFunctionDecl(
+      auto virtual_index = vtable_context.getMethodVTableIndex(method_decl);
+      if (virtual_index >= vtable.size()) {
+        vtable.resize(virtual_index + 1, SemIR::InstId::None);
+      }
+      vtable[virtual_index] = ImportCppFunctionDecl(
           context, SemIR::LocId(import_ir_inst_id),
           const_cast<clang::CXXMethodDecl*>(method_decl),
-          MakeVirtualFunctionSignature(context, method_decl)));
+          MakeVirtualFunctionSignature(context, method_decl));
     }
-    vtable.truncate(num_components);
     auto vtable_id = context.vtables().Add(
         {{.class_id = class_id,
           .virtual_functions_id = context.inst_blocks().Add(vtable),
diff --git a/toolchain/check/import_ref.cpp b/toolchain/check/import_ref.cpp
index d791ba879b5a..1f2b9cd257bd 100644
--- a/toolchain/check/import_ref.cpp
+++ b/toolchain/check/import_ref.cpp
@@ -2454,6 +2454,9 @@ static auto TryResolveTypedInst(ImportRefResolver& resolver,
 
   for (auto [import_vtable_entry_inst_id, local_vtable_entry_inst_id] :
        llvm::zip_equal(virtual_functions, lazy_virtual_functions)) {
+    if (!local_vtable_entry_inst_id.has_value()) {
+      continue;
+    }
     // Use LoadedImportRef for imported symbolic constant vtable entries so they
     // can carry attached constants necessary for applying specifics to these
     // constants when they are used.
diff --git a/toolchain/check/testdata/interop/cpp/class/import/class.carbon b/toolchain/check/testdata/interop/cpp/class/import/class.carbon
index 556c79f82361..8d7fff4a1b7d 100644
--- a/toolchain/check/testdata/interop/cpp/class/import/class.carbon
+++ b/toolchain/check/testdata/interop/cpp/class/import/class.carbon
@@ -522,6 +522,8 @@ fn GenericUse(p2: Generic(Cpp.Class1)) {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: vtable @Bar.vtable {
+// CHECK:STDOUT:   invalid
+// CHECK:STDOUT:   invalid
 // CHECK:STDOUT:   imports.%Bar.f.decl
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon b/toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon
index 1a87134a6e52..0cb07add47a2 100644
--- a/toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon
+++ b/toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon
@@ -102,7 +102,6 @@ auto DoThing() -> int {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTV11FurtherBase = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: @"_CDerived.Main.$vtable" = unnamed_addr constant [3 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZN11FurtherBase17further_base_funcEv to i64), i64 ptrtoint (ptr @"_CDerived.Main.$vtable" to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @_ZN4Base4funcEv to i64), i64 ptrtoint (ptr @"_CDerived.Main.$vtable" to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint (ptr @_Cother_func.Derived.Main to i64), i64 ptrtoint (ptr @"_CDerived.Main.$vtable" to i64)) to i32)]
 // CHECK:STDOUT: @_ZTVN6Carbon7DerivedE = linkonce_odr dso_local unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr @_ZTIN6Carbon7DerivedE, ptr @_ZN11FurtherBase17further_base_funcEv, ptr @_ZN4Base4funcEv] }, comdat, align 8
 // CHECK:STDOUT: @_ZTIN6Carbon7DerivedE = linkonce_odr dso_local constant { ptr, ptr, ptr } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2), ptr @_ZTSN6Carbon7DerivedE, ptr @_ZTI4Base }, comdat, align 8
 // CHECK:STDOUT: @_ZTVN10__cxxabiv120__si_class_type_infoE = external global [0 x ptr]
@@ -275,8 +274,8 @@ auto DoThing() -> int {
 // CHECK:STDOUT: uselistorder ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2), { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @_ZN6Carbon7DerivedC2Ev, { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @_ZN6Carbon7DerivedD2Ev, { 2, 1, 0 }
-// CHECK:STDOUT: uselistorder ptr @_ZN11FurtherBase17further_base_funcEv, { 3, 2, 1, 0 }
-// CHECK:STDOUT: uselistorder ptr @_ZN4Base4funcEv, { 2, 1, 0 }
+// CHECK:STDOUT: uselistorder ptr @_ZN11FurtherBase17further_base_funcEv, { 2, 1, 0 }
+// CHECK:STDOUT: uselistorder ptr @_ZN4Base4funcEv, { 1, 0 }
 // 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 = { 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" }
diff --git a/toolchain/lower/testdata/interop/cpp/class/virtual_fn.carbon b/toolchain/lower/testdata/interop/cpp/class/virtual_fn.carbon
index ae31da0c7515..34d400277f03 100644
--- a/toolchain/lower/testdata/interop/cpp/class/virtual_fn.carbon
+++ b/toolchain/lower/testdata/interop/cpp/class/virtual_fn.carbon
@@ -19,15 +19,18 @@ import Cpp;
 inline Cpp '''
 struct A {
   virtual ~A() = 0;
+  virtual void F() const;
 };
 ''';
 
 class Final {
   extend base: Cpp.A;
+  override fn F[self: Self]();
 }
 
 base class Base {
   extend base: Cpp.A;
+  override fn F[self: Self]();
 }
 
 inline Cpp '''
@@ -71,29 +74,19 @@ void delete_new_Base() {
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTSN6Carbon5FinalE = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: $_ZTI1A = comdat any
-// CHECK:STDOUT:
-// CHECK:STDOUT: $_ZTS1A = comdat any
-// CHECK:STDOUT:
-// CHECK:STDOUT: $_ZTV1A = comdat any
-// CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTVN6Carbon4BaseE = comdat any
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTIN6Carbon4BaseE = comdat any
 // CHECK:STDOUT:
 // CHECK:STDOUT: $_ZTSN6Carbon4BaseE = comdat any
 // CHECK:STDOUT:
-// CHECK:STDOUT: @"_CFinal.Main.$vtable" = unnamed_addr constant [0 x i32] zeroinitializer
-// CHECK:STDOUT: @"_CBase.Main.$vtable" = unnamed_addr constant [0 x i32] zeroinitializer
-// CHECK:STDOUT: @_ZTVN6Carbon5FinalE = linkonce_odr dso_local unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr @_ZTIN6Carbon5FinalE, ptr @_ZN6Carbon5FinalD2Ev, ptr @_ZN6Carbon5FinalD0Ev] }, comdat, align 8
+// CHECK:STDOUT: @_ZTVN6Carbon5FinalE = linkonce_odr dso_local unnamed_addr constant { [5 x ptr] } { [5 x ptr] [ptr null, ptr @_ZTIN6Carbon5FinalE, ptr @_ZN6Carbon5FinalD2Ev, ptr @_ZN6Carbon5FinalD0Ev, ptr @_ZNK1A1FEv] }, comdat, align 8
 // CHECK:STDOUT: @_ZTIN6Carbon5FinalE = linkonce_odr dso_local constant { ptr, ptr, ptr } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2), ptr @_ZTSN6Carbon5FinalE, ptr @_ZTI1A }, comdat, align 8
 // CHECK:STDOUT: @_ZTVN10__cxxabiv120__si_class_type_infoE = external global [0 x ptr]
 // CHECK:STDOUT: @_ZTSN6Carbon5FinalE = linkonce_odr dso_local constant [16 x i8] c"N6Carbon5FinalE\00", comdat, align 1
-// CHECK:STDOUT: @_ZTI1A = linkonce_odr dso_local constant { ptr, ptr } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), ptr @_ZTS1A }, comdat, align 8
-// CHECK:STDOUT: @_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr]
-// CHECK:STDOUT: @_ZTS1A = linkonce_odr dso_local constant [3 x i8] c"1A\00", comdat, align 1
-// CHECK:STDOUT: @_ZTV1A = linkonce_odr dso_local unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr @_ZTI1A, ptr @__cxa_pure_virtual, ptr @__cxa_pure_virtual] }, comdat, align 8
-// CHECK:STDOUT: @_ZTVN6Carbon4BaseE = linkonce_odr dso_local unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr @_ZTIN6Carbon4BaseE, ptr @_ZN6Carbon4BaseD2Ev, ptr @_ZN6Carbon4BaseD0Ev] }, comdat, align 8
+// CHECK:STDOUT: @_ZTI1A = external constant ptr
+// CHECK:STDOUT: @_ZTV1A = available_externally unnamed_addr constant { [5 x ptr] } { [5 x ptr] [ptr null, ptr @_ZTI1A, ptr @__cxa_pure_virtual, ptr @__cxa_pure_virtual, ptr @_ZNK1A1FEv] }, align 8
+// CHECK:STDOUT: @_ZTVN6Carbon4BaseE = linkonce_odr dso_local unnamed_addr constant { [5 x ptr] } { [5 x ptr] [ptr null, ptr @_ZTIN6Carbon4BaseE, ptr @_ZN6Carbon4BaseD2Ev, ptr @_ZN6Carbon4BaseD0Ev, ptr @_ZNK1A1FEv] }, comdat, align 8
 // CHECK:STDOUT: @_ZTIN6Carbon4BaseE = linkonce_odr dso_local constant { ptr, ptr, ptr } { ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2), ptr @_ZTSN6Carbon4BaseE, ptr @_ZTI1A }, comdat, align 8
 // CHECK:STDOUT: @_ZTSN6Carbon4BaseE = linkonce_odr dso_local constant [15 x i8] c"N6Carbon4BaseE\00", comdat, align 1
 // CHECK:STDOUT:
@@ -101,21 +94,21 @@ void delete_new_Base() {
 // CHECK:STDOUT: define dso_local void @_Z16delete_new_Finalv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %p = alloca ptr, align 8
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %p) #7
-// CHECK:STDOUT:   %call = call noalias noundef nonnull ptr @_Znwm(i64 noundef 8) #8
-// CHECK:STDOUT:   call void @_ZN6Carbon5FinalC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %call) #7
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %p) #8
+// CHECK:STDOUT:   %call = call noalias noundef nonnull ptr @_Znwm(i64 noundef 8) #10
+// CHECK:STDOUT:   call void @_ZN6Carbon5FinalC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %call) #8
 // CHECK:STDOUT:   store ptr %call, ptr %p, align 8, !tbaa !11
 // CHECK:STDOUT:   %0 = load ptr, ptr %p, align 8, !tbaa !11
 // CHECK:STDOUT:   %isnull = icmp eq ptr %0, null
 // CHECK:STDOUT:   br i1 %isnull, label %delete.end, label %delete.notnull
 // CHECK:STDOUT:
 // CHECK:STDOUT: delete.notnull:                                   ; preds = %entry
-// CHECK:STDOUT:   call void @_ZN6Carbon5FinalD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %0) #7
-// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %0, i64 noundef 8) #9
+// CHECK:STDOUT:   call void @_ZN6Carbon5FinalD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %0) #8
+// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %0, i64 noundef 8) #11
 // CHECK:STDOUT:   br label %delete.end
 // CHECK:STDOUT:
 // CHECK:STDOUT: delete.end:                                       ; preds = %delete.notnull, %entry
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %p) #7
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %p) #8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -131,8 +124,8 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   call void @_ZN1AC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %this1) #7
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTVN6Carbon5FinalE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
+// CHECK:STDOUT:   call void @_ZN1AC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %this1) #8
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 24) ({ [5 x ptr] }, ptr @_ZTVN6Carbon5FinalE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -143,7 +136,7 @@ void delete_new_Base() {
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
 // CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.Final.Main"(ptr noundef nonnull align 8 dereferenceable(8) %this1)
-// CHECK:STDOUT:   call void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #7
+// CHECK:STDOUT:   call void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -157,9 +150,9 @@ void delete_new_Base() {
 // CHECK:STDOUT: define dso_local void @_Z15delete_new_Basev() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %p = alloca ptr, align 8
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %p) #7
-// CHECK:STDOUT:   %call = call noalias noundef nonnull ptr @_Znwm(i64 noundef 8) #8
-// CHECK:STDOUT:   call void @_ZN6Carbon4BaseC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %call) #7
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %p) #8
+// CHECK:STDOUT:   %call = call noalias noundef nonnull ptr @_Znwm(i64 noundef 8) #10
+// CHECK:STDOUT:   call void @_ZN6Carbon4BaseC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %call) #8
 // CHECK:STDOUT:   store ptr %call, ptr %p, align 8, !tbaa !16
 // CHECK:STDOUT:   %0 = load ptr, ptr %p, align 8, !tbaa !16
 // CHECK:STDOUT:   %isnull = icmp eq ptr %0, null
@@ -169,11 +162,11 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %vtable = load ptr, ptr %0, align 8, !tbaa !14
 // CHECK:STDOUT:   %vfn = getelementptr inbounds ptr, ptr %vtable, i64 1
 // CHECK:STDOUT:   %1 = load ptr, ptr %vfn, align 8
-// CHECK:STDOUT:   call void %1(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %0) #7
+// CHECK:STDOUT:   call void %1(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %0) #8
 // CHECK:STDOUT:   br label %delete.end
 // CHECK:STDOUT:
 // CHECK:STDOUT: delete.end:                                       ; preds = %delete.notnull, %entry
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %p) #7
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %p) #8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -183,53 +176,70 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !16
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   call void @_ZN1AC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %this1) #7
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTVN6Carbon4BaseE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
+// CHECK:STDOUT:   call void @_ZN1AC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %this1) #8
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 24) ({ [5 x ptr] }, ptr @_ZTVN6Carbon4BaseE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.Final.Main"(ptr %self) #5 !dbg !18 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress nounwind uwtable
+// CHECK:STDOUT: define internal void @_ZNK1A1FEv.carbon_thunk._(ptr noundef nonnull align 8 dereferenceable(8) %this) #5 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @"_COp.4472d163614a5082:core.Destroy.Core"(ptr %self), !dbg !24
-// CHECK:STDOUT:   ret void, !dbg !24
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !18
+// CHECK:STDOUT:   %0 = load ptr, ptr %this.addr, align 8, !tbaa !18, !nonnull !20, !align !21
+// CHECK:STDOUT:   %vtable = load ptr, ptr %0, align 8, !tbaa !14
+// CHECK:STDOUT:   %vfn = getelementptr inbounds ptr, ptr %vtable, i64 2
+// CHECK:STDOUT:   %1 = load ptr, ptr %vfn, align 8
+// CHECK:STDOUT:   call void %1(ptr noundef nonnull align 8 dereferenceable(8) %0)
+// CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare void @_ZN1AD1Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8)) unnamed_addr #6
+// CHECK:STDOUT: declare void @_CF.Final.Main(ptr)
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.446491dd079aaad2:core.Destroy.Core"(ptr %self) #7 !dbg !25 {
+// CHECK:STDOUT: declare void @_CF.Base.Main(ptr)
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.Final.Main"(ptr %self) #6 !dbg !22 {
 // CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @"_COp.4472d163614a5082:core.Destroy.Core"(ptr %self), !dbg !28
 // CHECK:STDOUT:   ret void, !dbg !28
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.4472d163614a5082:core.Destroy.Core"(ptr %self) #7 !dbg !29 {
+// CHECK:STDOUT: declare void @_ZN1AD1Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8)) unnamed_addr #7
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.446491dd079aaad2:core.Destroy.Core"(ptr %self) #8 !dbg !29 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
-// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.Base.Main"(ptr %self) #5 !dbg !33 {
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.4472d163614a5082:core.Destroy.Core"(ptr %self) #8 !dbg !33 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @"_COp.96a711151205ee34:core.Destroy.Core"(ptr %self), !dbg !36
 // CHECK:STDOUT:   ret void, !dbg !36
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.96a711151205ee34:core.Destroy.Core"(ptr %self) #7 !dbg !37 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.Base.Main"(ptr %self) #6 !dbg !37 {
 // CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @"_COp.96a711151205ee34:core.Destroy.Core"(ptr %self), !dbg !40
 // CHECK:STDOUT:   ret void, !dbg !40
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.96a711151205ee34:core.Destroy.Core"(ptr %self) #8 !dbg !41 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !44
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
 // CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1AC2Ev(ptr noundef nonnull align 8 dereferenceable(8) %this) unnamed_addr #3 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 !41
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !18
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTV1A, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 24) ({ [5 x ptr] }, ptr @_ZTV1A, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -239,15 +249,17 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   call void @_ZN6Carbon5FinalD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #7
-// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %this1, i64 noundef 8) #9
+// CHECK:STDOUT:   call void @_ZN6Carbon5FinalD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #8
+// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %this1, i64 noundef 8) #11
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_ZNK1A1FEv(ptr noundef nonnull align 8 dereferenceable(8)) unnamed_addr #9
+// CHECK:STDOUT:
 // CHECK:STDOUT: declare void @__cxa_pure_virtual() unnamed_addr
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: declare void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8)) unnamed_addr #6
+// CHECK:STDOUT: declare void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8)) unnamed_addr #7
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
 // CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon4BaseD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this) unnamed_addr #3 comdat align 2 {
@@ -255,9 +267,9 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !16
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTVN6Carbon4BaseE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
+// CHECK:STDOUT:   store ptr getelementptr inbounds inrange(-16, 24) ({ [5 x ptr] }, ptr @_ZTVN6Carbon4BaseE, i32 0, i32 0, i32 2), ptr %this1, align 8, !tbaa !14
 // CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.Base.Main"(ptr noundef nonnull align 8 dereferenceable(8) %this1)
-// CHECK:STDOUT:   call void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #7
+// CHECK:STDOUT:   call void @_ZN1AD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #8
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -267,14 +279,15 @@ void delete_new_Base() {
 // CHECK:STDOUT:   %this.addr = alloca ptr, align 8
 // CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !16
 // CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
-// CHECK:STDOUT:   call void @_ZN6Carbon4BaseD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #7
-// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %this1, i64 noundef 8) #9
+// CHECK:STDOUT:   call void @_ZN6Carbon4BaseD2Ev(ptr noundef nonnull align 8 dead_on_return(8) dereferenceable(8) %this1) #8
+// CHECK:STDOUT:   call void @_ZdlPvm(ptr noundef %this1, i64 noundef 8) #11
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; uselistorder directives
 // CHECK:STDOUT: uselistorder ptr @_ZN6Carbon5FinalD2Ev, { 2, 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @_ZN1AC2Ev, { 1, 0 }
+// CHECK:STDOUT: uselistorder ptr @_ZNK1A1FEv, { 2, 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @__cxa_pure_virtual, { 1, 0 }
 // CHECK:STDOUT: uselistorder ptr @_ZN6Carbon4BaseD2Ev, { 1, 0 }
 // CHECK:STDOUT:
@@ -283,11 +296,13 @@ void delete_new_Base() {
 // CHECK:STDOUT: attributes #2 = { nobuiltin allocsize(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: attributes #4 = { nobuiltin 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 #5 = { alwaysinline nounwind }
-// CHECK:STDOUT: attributes #6 = { 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 #7 = { nounwind }
-// CHECK:STDOUT: attributes #8 = { builtin allocsize(0) }
-// CHECK:STDOUT: attributes #9 = { builtin nounwind }
+// CHECK:STDOUT: attributes #5 = { 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 #6 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #7 = { 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 #8 = { nounwind }
+// CHECK:STDOUT: attributes #9 = { "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 #10 = { builtin allocsize(0) }
+// CHECK:STDOUT: attributes #11 = { builtin nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -311,28 +326,30 @@ void delete_new_Base() {
 // CHECK:STDOUT: !15 = !{!"vtable pointer", !10, i64 0}
 // CHECK:STDOUT: !16 = !{!17, !17, i64 0}
 // CHECK:STDOUT: !17 = !{!"p1 _ZTSN6Carbon4BaseE", !13, i64 0}
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.Final.Main", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
-// CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
-// CHECK:STDOUT: !20 = !{null, !21}
-// CHECK:STDOUT: !21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
-// CHECK:STDOUT: !22 = !{!23}
-// CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !18, type: !21)
-// CHECK:STDOUT: !24 = !DILocation(line: 11, column: 1, scope: !18)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp.446491dd079aaad2:core.Destroy.Core", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
+// CHECK:STDOUT: !18 = !{!19, !19, i64 0}
+// CHECK:STDOUT: !19 = !{!"p1 _ZTS1A", !13, i64 0}
+// CHECK:STDOUT: !20 = !{}
+// CHECK:STDOUT: !21 = !{i64 8}
+// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.Final.Main", scope: null, file: !6, line: 12, type: !23, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
+// CHECK:STDOUT: !23 = !DISubroutineType(types: !24)
+// CHECK:STDOUT: !24 = !{null, !25}
+// CHECK:STDOUT: !25 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
 // CHECK:STDOUT: !26 = !{!27}
-// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !25, type: !21)
-// CHECK:STDOUT: !28 = !DILocation(line: 11, column: 1, scope: !25)
-// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "Op", linkageName: "_COp.4472d163614a5082:core.Destroy.Core", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
+// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !22, type: !25)
+// CHECK:STDOUT: !28 = !DILocation(line: 12, column: 1, scope: !22)
+// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "Op", linkageName: "_COp.446491dd079aaad2:core.Destroy.Core", scope: null, file: !6, line: 12, type: !23, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
 // CHECK:STDOUT: !30 = !{!31}
-// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !21)
-// CHECK:STDOUT: !32 = !DILocation(line: 11, column: 1, scope: !29)
-// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.Base.Main", scope: null, file: !6, line: 15, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !34)
+// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !25)
+// CHECK:STDOUT: !32 = !DILocation(line: 12, column: 1, scope: !29)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.4472d163614a5082:core.Destroy.Core", scope: null, file: !6, line: 12, type: !23, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !34)
 // CHECK:STDOUT: !34 = !{!35}
-// CHECK:STDOUT: !35 = !DILocalVariable(arg: 1, scope: !33, type: !21)
-// CHECK:STDOUT: !36 = !DILocation(line: 15, column: 1, scope: !33)
-// CHECK:STDOUT: !37 = distinct !DISubprogram(name: "Op", linkageName: "_COp.96a711151205ee34:core.Destroy.Core", scope: null, file: !6, line: 15, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !38)
+// CHECK:STDOUT: !35 = !DILocalVariable(arg: 1, scope: !33, type: !25)
+// CHECK:STDOUT: !36 = !DILocation(line: 12, column: 1, scope: !33)
+// CHECK:STDOUT: !37 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.Base.Main", scope: null, file: !6, line: 17, type: !23, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !38)
 // CHECK:STDOUT: !38 = !{!39}
-// CHECK:STDOUT: !39 = !DILocalVariable(arg: 1, scope: !37, type: !21)
-// CHECK:STDOUT: !40 = !DILocation(line: 15, column: 1, scope: !37)
-// CHECK:STDOUT: !41 = !{!42, !42, i64 0}
-// CHECK:STDOUT: !42 = !{!"p1 _ZTS1A", !13, i64 0}
+// CHECK:STDOUT: !39 = !DILocalVariable(arg: 1, scope: !37, type: !25)
+// CHECK:STDOUT: !40 = !DILocation(line: 17, column: 1, scope: !37)
+// CHECK:STDOUT: !41 = distinct !DISubprogram(name: "Op", linkageName: "_COp.96a711151205ee34:core.Destroy.Core", scope: null, file: !6, line: 17, type: !23, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !42)
+// CHECK:STDOUT: !42 = !{!43}
+// CHECK:STDOUT: !43 = !DILocalVariable(arg: 1, scope: !41, type: !25)
+// CHECK:STDOUT: !44 = !DILocation(line: 17, column: 1, scope: !41)