Index: clang/lib/AST/Interp/ByteCodeExprGen.h
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.h
+++ clang/lib/AST/Interp/ByteCodeExprGen.h
@@ -96,6 +96,7 @@
   bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
   bool VisitTypeTraitExpr(const TypeTraitExpr *E);
   bool VisitLambdaExpr(const LambdaExpr *E);
+  bool VisitPredefinedExpr(const PredefinedExpr *E);
 
 protected:
   bool visitExpr(const Expr *E) override;
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1004,6 +1004,14 @@
   return true;
 }
 
+template <class Emitter>
+bool ByteCodeExprGen<Emitter>::VisitPredefinedExpr(const PredefinedExpr *E) {
+  if (DiscardResult)
+    return true;
+
+  return this->visit(E->getFunctionName());
+}
+
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
   if (E->containsErrors())
     return false;
Index: clang/test/AST/Interp/literals.cpp
===================================================================
--- clang/test/AST/Interp/literals.cpp
+++ clang/test/AST/Interp/literals.cpp
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++11 -verify %s
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++20 -verify %s
-// RUN: %clang_cc1 -std=c++11 -verify=ref %s
-// RUN: %clang_cc1 -std=c++20 -verify=ref %s
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -fms-extensions -std=c++11 -verify %s
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -fms-extensions -std=c++20 -verify %s
+// RUN: %clang_cc1 -std=c++11 -fms-extensions -verify=ref %s
+// RUN: %clang_cc1 -std=c++20 -fms-extensions -verify=ref %s
 
 #define INT_MIN (~__INT_MAX__)
 #define INT_MAX __INT_MAX__
@@ -831,3 +831,27 @@
 }
 
 #endif
+
+namespace PredefinedExprs {
+#if __cplusplus >= 201402L
+  template<typename CharT>
+  constexpr bool strings_match(const CharT *str1, const CharT *str2) {
+    while (*str1 && *str2) {
+      if (*str1++ != *str2++)
+        return false;
+    };
+
+    return *str1 == *str2;
+  }
+
+  void foo() {
+    static_assert(strings_match(__FUNCDNAME__, "_ZN15PredefinedExprs3fooEv"), "");
+    static_assert(strings_match(__FUNCSIG__, "void __cdecl PredefinedExprs::foo(void)"), "");
+    static_assert(strings_match(L__FUNCSIG__, L"void __cdecl PredefinedExprs::foo(void)"), "");
+    static_assert(strings_match(L__FUNCTION__, L"foo"), "");
+    static_assert(strings_match(__FUNCTION__, "foo"), "");
+    static_assert(strings_match(__func__, "foo"), "");
+    static_assert(strings_match(__PRETTY_FUNCTION__, "void PredefinedExprs::foo()"), "");
+  }
+#endif
+}