diff --git a/toolchain/check/eval.cpp b/toolchain/check/eval.cpp
index eeb4f2d2e0a2..a7bb994c56ea 100644
--- a/toolchain/check/eval.cpp
+++ b/toolchain/check/eval.cpp
@@ -1512,6 +1512,10 @@ static auto MakeFacetTypeResult(Context& context,
 }
 
 // Implementation for `TryEvalInst`, wrapping `Context` with `EvalContext`.
+//
+// Tail call should not be diagnosed as recursion.
+// https://github.com/llvm/llvm-project/issues/125724
+// NOLINTNEXTLINE(misc-no-recursion): Tail call.
 static auto TryEvalInstInContext(EvalContext& eval_context,
                                  SemIR::InstId inst_id, SemIR::Inst inst)
     -> SemIR::ConstantId {
@@ -1898,10 +1902,43 @@ static auto TryEvalInstInContext(EvalContext& eval_context,
       return MakeConstantResult(eval_context.context(), bind, phase);
     }
 
-    // These semantic wrappers don't change the constant value.
+    // AsCompatible changes the type of the source instruction; its constant
+    // value, if there is one, needs to be modified to be of the same type.
     case CARBON_KIND(SemIR::AsCompatible inst): {
-      return eval_context.GetConstantValue(inst.source_id);
+      auto value = eval_context.GetConstantValue(inst.source_id);
+      if (!value.is_constant()) {
+        return value;
+      }
+
+      auto from_phase = Phase::Template;
+      auto value_inst_id =
+          GetConstantValue(eval_context, inst.source_id, &from_phase);
+
+      auto to_phase = Phase::Template;
+      auto type_id = GetConstantValue(eval_context, inst.type_id, &to_phase);
+
+      auto value_inst = eval_context.insts().Get(value_inst_id);
+      value_inst.SetType(type_id);
+
+      if (to_phase >= from_phase) {
+        // If moving from a template constant value to a symbolic type, the new
+        // constant value takes on the phase of the new type. We're adding the
+        // symbolic bit to the new constant value due to the presence of a
+        // symbolic type.
+        return MakeConstantResult(eval_context.context(), value_inst, to_phase);
+      } else {
+        // If moving from a symbolic constant value to a template type, the new
+        // constant value has a phase that depends on what is in the value. If
+        // there is anything symbolic within the value, then it's symbolic. We
+        // can't easily determine that here without evaluating a new constant
+        // value. See
+        // https://github.com/carbon-language/carbon-lang/pull/4881#discussion_r1939961372
+        [[clang::musttail]] return TryEvalInstInContext(
+            eval_context, SemIR::InstId::None, value_inst);
+      }
     }
+
+    // These semantic wrappers don't change the constant value.
     case CARBON_KIND(SemIR::BindAlias typed_inst): {
       return eval_context.GetConstantValue(typed_inst.value_id);
     }
diff --git a/toolchain/check/testdata/as/adapter_conversion.carbon b/toolchain/check/testdata/as/adapter_conversion.carbon
index ce979da67938..c06ca8fc45a7 100644
--- a/toolchain/check/testdata/as/adapter_conversion.carbon
+++ b/toolchain/check/testdata/as/adapter_conversion.carbon
@@ -377,6 +377,7 @@ var b: B = {.x = 1} as B;
 // CHECK:STDOUT:   %Convert.bound: <bound method> = bound_method %int_1.5b8, %Convert.197 [template]
 // CHECK:STDOUT:   %Convert.specific_fn: <specific function> = specific_function %Convert.bound, @Convert.5(%int_32) [template]
 // CHECK:STDOUT:   %int_1.5d2: %i32 = int_value 1 [template]
+// CHECK:STDOUT:   %int_1.e78: %A = int_value 1 [template]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
@@ -435,8 +436,8 @@ var b: B = {.x = 1} as B;
 // CHECK:STDOUT:   %.loc8_15.1: %i32 = value_of_initializer %int.convert_checked [template = constants.%int_1.5d2]
 // CHECK:STDOUT:   %.loc8_15.2: %i32 = converted %int_1, %.loc8_15.1 [template = constants.%int_1.5d2]
 // CHECK:STDOUT:   %A.ref: type = name_ref A, file.%A.decl [template = constants.%A]
-// CHECK:STDOUT:   %.loc8_23.1: %A = as_compatible %.loc8_15.2 [template = constants.%int_1.5d2]
-// CHECK:STDOUT:   %.loc8_23.2: %A = converted %.loc8_15.2, %.loc8_23.1 [template = constants.%int_1.5d2]
+// CHECK:STDOUT:   %.loc8_23.1: %A = as_compatible %.loc8_15.2 [template = constants.%int_1.e78]
+// CHECK:STDOUT:   %.loc8_23.2: %A = converted %.loc8_15.2, %.loc8_23.1 [template = constants.%int_1.e78]
 // CHECK:STDOUT:   %a.ref: %A = name_ref a, file.%a
 // CHECK:STDOUT:   %int_32.loc9: Core.IntLiteral = int_value 32 [template = constants.%int_32]
 // CHECK:STDOUT:   %i32.loc9: type = class_type @Int, @Int(constants.%int_32) [template = constants.%i32]
@@ -455,6 +456,7 @@ var b: B = {.x = 1} as B;
 // CHECK:STDOUT:   %C: type = class_type @C [template]
 // CHECK:STDOUT:   %D: type = class_type @D [template]
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [template]
+// CHECK:STDOUT:   %D.val: %D = struct_value () [template]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: imports {
@@ -531,8 +533,8 @@ var b: B = {.x = 1} as B;
 // CHECK:STDOUT:   %.loc9_13: %empty_struct_type = struct_literal ()
 // CHECK:STDOUT:   %D.ref: type = name_ref D, file.%D.decl [template = constants.%D]
 // CHECK:STDOUT:   %empty_struct: %empty_struct_type = struct_value () [template = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc9_15.1: %D = as_compatible %empty_struct [template = constants.%empty_struct]
-// CHECK:STDOUT:   %.loc9_15.2: %D = converted %.loc9_13, %.loc9_15.1 [template = constants.%empty_struct]
+// CHECK:STDOUT:   %.loc9_15.1: %D = as_compatible %empty_struct [template = constants.%D.val]
+// CHECK:STDOUT:   %.loc9_15.2: %D = converted %.loc9_13, %.loc9_15.1 [template = constants.%D.val]
 // CHECK:STDOUT:   return
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
diff --git a/toolchain/check/testdata/function/builtin/no_prelude/adapted_type.carbon b/toolchain/check/testdata/function/builtin/no_prelude/adapted_type.carbon
index c8ece830142d..ca51499be658 100644
--- a/toolchain/check/testdata/function/builtin/no_prelude/adapted_type.carbon
+++ b/toolchain/check/testdata/function/builtin/no_prelude/adapted_type.carbon
@@ -56,16 +56,19 @@ fn Int(N: MyIntLiteral) -> type = "int.make_type_signed";
 // CHECK:STDOUT:   %Int.type: type = fn_type @Int [template]
 // CHECK:STDOUT:   %Int: %Int.type = struct_value () [template]
 // CHECK:STDOUT:   %MyInt32: type = class_type @MyInt32 [template]
-// CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [template]
-// CHECK:STDOUT:   %i32.builtin: type = int_type signed, %int_32 [template]
+// CHECK:STDOUT:   %int_32.be0: Core.IntLiteral = int_value 32 [template]
+// CHECK:STDOUT:   %int_32.4da: %MyIntLiteral = int_value 32 [template]
+// CHECK:STDOUT:   %i32.builtin: type = int_type signed, %int_32.4da [template]
 // CHECK:STDOUT:   %Make.type: type = fn_type @Make [template]
 // CHECK:STDOUT:   %Make: %Make.type = struct_value () [template]
-// CHECK:STDOUT:   %complete_type.f8a: <witness> = complete_type_witness %i32.builtin [template]
+// CHECK:STDOUT:   %complete_type.ec2: <witness> = complete_type_witness %i32.builtin [template]
 // CHECK:STDOUT:   %MyAdd.type: type = fn_type @MyAdd [template]
 // CHECK:STDOUT:   %MyAdd: %MyAdd.type = struct_value () [template]
 // CHECK:STDOUT:   %int_1.5b8: Core.IntLiteral = int_value 1 [template]
+// CHECK:STDOUT:   %int_1.383: %MyIntLiteral = int_value 1 [template]
 // CHECK:STDOUT:   %int_1.d74: %MyInt32 = int_value 1 [template]
 // CHECK:STDOUT:   %int_2.ecc: Core.IntLiteral = int_value 2 [template]
+// CHECK:STDOUT:   %int_2.a27: %MyIntLiteral = int_value 2 [template]
 // CHECK:STDOUT:   %int_2.eda: %MyInt32 = int_value 2 [template]
 // CHECK:STDOUT:   %int_3: %MyInt32 = int_value 3 [template]
 // CHECK:STDOUT: }
@@ -155,10 +158,10 @@ fn Int(N: MyIntLiteral) -> type = "int.make_type_signed";
 // CHECK:STDOUT:
 // CHECK:STDOUT: class @MyInt32 {
 // CHECK:STDOUT:   %Int.ref: %Int.type = name_ref Int, file.%Int.decl [template = constants.%Int]
-// CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32]
+// CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [template = constants.%int_32.be0]
 // CHECK:STDOUT:   %MyIntLiteral.ref: type = name_ref MyIntLiteral, file.%MyIntLiteral.decl [template = constants.%MyIntLiteral]
-// CHECK:STDOUT:   %.loc13_16.1: %MyIntLiteral = as_compatible %int_32 [template = constants.%int_32]
-// CHECK:STDOUT:   %.loc13_16.2: %MyIntLiteral = converted %int_32, %.loc13_16.1 [template = constants.%int_32]
+// CHECK:STDOUT:   %.loc13_16.1: %MyIntLiteral = as_compatible %int_32 [template = constants.%int_32.4da]
+// CHECK:STDOUT:   %.loc13_16.2: %MyIntLiteral = converted %int_32, %.loc13_16.1 [template = constants.%int_32.4da]
 // CHECK:STDOUT:   %int.make_type_signed: init type = call %Int.ref(%.loc13_16.2) [template = constants.%i32.builtin]
 // CHECK:STDOUT:   %.loc13_32.1: type = value_of_initializer %int.make_type_signed [template = constants.%i32.builtin]
 // CHECK:STDOUT:   %.loc13_32.2: type = converted %int.make_type_signed, %.loc13_32.1 [template = constants.%i32.builtin]
@@ -176,7 +179,7 @@ fn Int(N: MyIntLiteral) -> type = "int.make_type_signed";
 // CHECK:STDOUT:     %return.param.loc15: ref %MyInt32 = out_param runtime_param1
 // CHECK:STDOUT:     %return.loc15: ref %MyInt32 = return_slot %return.param.loc15
 // CHECK:STDOUT:   }
-// CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %i32.builtin [template = constants.%complete_type.f8a]
+// CHECK:STDOUT:   %complete_type: <witness> = complete_type_witness %i32.builtin [template = constants.%complete_type.ec2]
 // CHECK:STDOUT:   complete_type_witness = %complete_type
 // CHECK:STDOUT:
 // CHECK:STDOUT: !members:
@@ -199,15 +202,15 @@ fn Int(N: MyIntLiteral) -> type = "int.make_type_signed";
 // CHECK:STDOUT:   %Make.ref.loc22_31: %Make.type = name_ref Make, @MyInt32.%Make.decl [template = constants.%Make]
 // CHECK:STDOUT:   %int_1: Core.IntLiteral = int_value 1 [template = constants.%int_1.5b8]
 // CHECK:STDOUT:   %MyIntLiteral.ref.loc22_42: type = name_ref MyIntLiteral, file.%MyIntLiteral.decl [template = constants.%MyIntLiteral]
-// CHECK:STDOUT:   %.loc22_39.1: %MyIntLiteral = as_compatible %int_1 [template = constants.%int_1.5b8]
-// CHECK:STDOUT:   %.loc22_39.2: %MyIntLiteral = converted %int_1, %.loc22_39.1 [template = constants.%int_1.5b8]
+// CHECK:STDOUT:   %.loc22_39.1: %MyIntLiteral = as_compatible %int_1 [template = constants.%int_1.383]
+// CHECK:STDOUT:   %.loc22_39.2: %MyIntLiteral = converted %int_1, %.loc22_39.1 [template = constants.%int_1.383]
 // CHECK:STDOUT:   %int.convert_checked.loc22_54: init %MyInt32 = call %Make.ref.loc22_31(%.loc22_39.2) [template = constants.%int_1.d74]
 // CHECK:STDOUT:   %MyInt32.ref.loc22_57: type = name_ref MyInt32, file.%MyInt32.decl [template = constants.%MyInt32]
 // CHECK:STDOUT:   %Make.ref.loc22_64: %Make.type = name_ref Make, @MyInt32.%Make.decl [template = constants.%Make]
 // CHECK:STDOUT:   %int_2: Core.IntLiteral = int_value 2 [template = constants.%int_2.ecc]
 // CHECK:STDOUT:   %MyIntLiteral.ref.loc22_75: type = name_ref MyIntLiteral, file.%MyIntLiteral.decl [template = constants.%MyIntLiteral]
-// CHECK:STDOUT:   %.loc22_72.1: %MyIntLiteral = as_compatible %int_2 [template = constants.%int_2.ecc]
-// CHECK:STDOUT:   %.loc22_72.2: %MyIntLiteral = converted %int_2, %.loc22_72.1 [template = constants.%int_2.ecc]
+// CHECK:STDOUT:   %.loc22_72.1: %MyIntLiteral = as_compatible %int_2 [template = constants.%int_2.a27]
+// CHECK:STDOUT:   %.loc22_72.2: %MyIntLiteral = converted %int_2, %.loc22_72.1 [template = constants.%int_2.a27]
 // CHECK:STDOUT:   %int.convert_checked.loc22_87: init %MyInt32 = call %Make.ref.loc22_64(%.loc22_72.2) [template = constants.%int_2.eda]
 // CHECK:STDOUT:   %.loc22_54.1: %MyInt32 = value_of_initializer %int.convert_checked.loc22_54 [template = constants.%int_1.d74]
 // CHECK:STDOUT:   %.loc22_54.2: %MyInt32 = converted %int.convert_checked.loc22_54, %.loc22_54.1 [template = constants.%int_1.d74]
diff --git a/toolchain/check/testdata/impl/no_prelude/import_builtin_call.carbon b/toolchain/check/testdata/impl/no_prelude/import_builtin_call.carbon
index 874afa9c534e..d54a3f7f4089 100644
--- a/toolchain/check/testdata/impl/no_prelude/import_builtin_call.carbon
+++ b/toolchain/check/testdata/impl/no_prelude/import_builtin_call.carbon
@@ -1049,8 +1049,9 @@ var n: Int(64) = MakeFromClass(FromLiteral(64) as OtherInt);
 // CHECK:STDOUT:   %iN.builtin.9ef: type = int_type signed, %int.convert_checked.b6b [symbolic]
 // CHECK:STDOUT:   %require_complete.c7d: <witness> = require_complete_type %iN.builtin.9ef [symbolic]
 // CHECK:STDOUT:   %MakeFromClass.specific_fn.004: <specific function> = specific_function %MakeFromClass, @MakeFromClass(%N.335) [symbolic]
-// CHECK:STDOUT:   %ToLiteral.bound.395: <bound method> = bound_method %int_64.f82, %ToLiteral.ec2 [template]
-// CHECK:STDOUT:   %MakeFromClass.specific_fn.ad7: <specific function> = specific_function %MakeFromClass, @MakeFromClass(%int_64.f82) [template]
+// CHECK:STDOUT:   %int_64.06b: %OtherInt = int_value 64 [template]
+// CHECK:STDOUT:   %ToLiteral.bound.735: <bound method> = bound_method %int_64.06b, %ToLiteral.ec2 [template]
+// CHECK:STDOUT:   %MakeFromClass.specific_fn.61b: <specific function> = specific_function %MakeFromClass, @MakeFromClass(%int_64.06b) [template]
 // CHECK:STDOUT:   %complete_type.4a1: <witness> = complete_type_witness %i64.builtin [template]
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -1169,11 +1170,11 @@ var n: Int(64) = MakeFromClass(FromLiteral(64) as OtherInt);
 // CHECK:STDOUT:   %int_64.loc7: Core.IntLiteral = int_value 64 [template = constants.%int_64.fab]
 // CHECK:STDOUT:   %int.convert_checked.loc7: init %i32.builtin = call %FromLiteral.ref.loc7(%int_64.loc7) [template = constants.%int_64.f82]
 // CHECK:STDOUT:   %OtherInt.ref: type = name_ref OtherInt, imports.%Main.OtherInt [template = constants.%OtherInt]
-// CHECK:STDOUT:   %.loc7_48.1: init %OtherInt = as_compatible %int.convert_checked.loc7 [template = constants.%int_64.f82]
-// CHECK:STDOUT:   %.loc7_48.2: init %OtherInt = converted %int.convert_checked.loc7, %.loc7_48.1 [template = constants.%int_64.f82]
-// CHECK:STDOUT:   %.loc7_59.1: %OtherInt = value_of_initializer %.loc7_48.2 [template = constants.%int_64.f82]
-// CHECK:STDOUT:   %.loc7_59.2: %OtherInt = converted %.loc7_48.2, %.loc7_59.1 [template = constants.%int_64.f82]
-// CHECK:STDOUT:   %MakeFromClass.specific_fn: <specific function> = specific_function %MakeFromClass.ref, @MakeFromClass(constants.%int_64.f82) [template = constants.%MakeFromClass.specific_fn.ad7]
+// CHECK:STDOUT:   %.loc7_48.1: init %OtherInt = as_compatible %int.convert_checked.loc7 [template = constants.%int_64.06b]
+// CHECK:STDOUT:   %.loc7_48.2: init %OtherInt = converted %int.convert_checked.loc7, %.loc7_48.1 [template = constants.%int_64.06b]
+// CHECK:STDOUT:   %.loc7_59.1: %OtherInt = value_of_initializer %.loc7_48.2 [template = constants.%int_64.06b]
+// CHECK:STDOUT:   %.loc7_59.2: %OtherInt = converted %.loc7_48.2, %.loc7_59.1 [template = constants.%int_64.06b]
+// CHECK:STDOUT:   %MakeFromClass.specific_fn: <specific function> = specific_function %MakeFromClass.ref, @MakeFromClass(constants.%int_64.06b) [template = constants.%MakeFromClass.specific_fn.61b]
 // CHECK:STDOUT:   %MakeFromClass.call: init %i64.builtin = call %MakeFromClass.specific_fn()
 // CHECK:STDOUT:   assign file.%n.var, %MakeFromClass.call
 // CHECK:STDOUT:   return
@@ -1217,15 +1218,15 @@ var n: Int(64) = MakeFromClass(FromLiteral(64) as OtherInt);
 // CHECK:STDOUT:
 // CHECK:STDOUT: specific @MakeFromClass(%N) {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @MakeFromClass(constants.%int_64.f82) {
-// CHECK:STDOUT:   %N => constants.%int_64.f82
-// CHECK:STDOUT:   %N.patt => constants.%int_64.f82
-// CHECK:STDOUT:   %ToLiteral.bound => constants.%ToLiteral.bound.395
+// CHECK:STDOUT: specific @MakeFromClass(constants.%int_64.06b) {
+// CHECK:STDOUT:   %N => constants.%int_64.06b
+// CHECK:STDOUT:   %N.patt => constants.%int_64.06b
+// CHECK:STDOUT:   %ToLiteral.bound => constants.%ToLiteral.bound.735
 // CHECK:STDOUT:   %int.convert_checked => constants.%int_64.fab
 // CHECK:STDOUT:   %iN.builtin => constants.%i64.builtin
 // CHECK:STDOUT:
 // CHECK:STDOUT: !definition:
 // CHECK:STDOUT:   %require_complete => constants.%complete_type.4a1
-// CHECK:STDOUT:   %MakeFromClass.specific_fn => constants.%MakeFromClass.specific_fn.ad7
+// CHECK:STDOUT:   %MakeFromClass.specific_fn => constants.%MakeFromClass.specific_fn.61b
 // CHECK:STDOUT: }
 // CHECK:STDOUT: