diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -1993,7 +1993,7 @@
 
 private:
   PredefinedExpr(SourceLocation L, QualType FNTy, IdentKind IK,
-                 StringLiteral *SL);
+                 bool TreatAsStringLiteral, StringLiteral *SL);
 
   explicit PredefinedExpr(EmptyShell Empty, bool HasFunctionName);
 
@@ -2009,7 +2009,8 @@
 public:
   /// Create a PredefinedExpr.
   static PredefinedExpr *Create(const ASTContext &Ctx, SourceLocation L,
-                                QualType FNTy, IdentKind IK, StringLiteral *SL);
+                                QualType FNTy, IdentKind IK,
+                                bool TreatAsStringLiteral, StringLiteral *SL);
 
   /// Create an empty PredefinedExpr.
   static PredefinedExpr *CreateEmpty(const ASTContext &Ctx,
@@ -2019,6 +2020,10 @@
     return static_cast<IdentKind>(PredefinedExprBits.Kind);
   }
 
+  bool getTreatAsStringLiteral() const {
+    return PredefinedExprBits.TreatAsStringLiteral;
+  }
+
   SourceLocation getLocation() const { return PredefinedExprBits.Loc; }
   void setLocation(SourceLocation L) { PredefinedExprBits.Loc = L; }
 
diff --git a/clang/include/clang/AST/IgnoreExpr.h b/clang/include/clang/AST/IgnoreExpr.h
--- a/clang/include/clang/AST/IgnoreExpr.h
+++ b/clang/include/clang/AST/IgnoreExpr.h
@@ -166,6 +166,11 @@
       return CE->getChosenSubExpr();
   }
 
+  else if (auto *PE = dyn_cast<PredefinedExpr>(E)) {
+    if (PE->getTreatAsStringLiteral())
+      return PE->getFunctionName();
+  }
+
   return E;
 }
 
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -364,6 +364,8 @@
     /// for the predefined identifier.
     unsigned HasFunctionName : 1;
 
+    unsigned TreatAsStringLiteral : 1;
+
     /// The location of this PredefinedExpr.
     SourceLocation Loc;
   };
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -7068,7 +7068,8 @@
     return std::move(Err);
 
   return PredefinedExpr::Create(Importer.getToContext(), ToBeginLoc, ToType,
-                                E->getIdentKind(), ToFunctionName);
+                                E->getIdentKind(), E->getTreatAsStringLiteral(),
+                                ToFunctionName);
 }
 
 ExpectedStmt ASTNodeImporter::VisitDeclRefExpr(DeclRefExpr *E) {
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -663,13 +663,14 @@
 }
 
 PredefinedExpr::PredefinedExpr(SourceLocation L, QualType FNTy, IdentKind IK,
-                               StringLiteral *SL)
+                               bool TreatAsStringLiteral, StringLiteral *SL)
     : Expr(PredefinedExprClass, FNTy, VK_LValue, OK_Ordinary) {
   PredefinedExprBits.Kind = IK;
   assert((getIdentKind() == IK) &&
          "IdentKind do not fit in PredefinedExprBitfields!");
   bool HasFunctionName = SL != nullptr;
   PredefinedExprBits.HasFunctionName = HasFunctionName;
+  PredefinedExprBits.TreatAsStringLiteral = TreatAsStringLiteral;
   PredefinedExprBits.Loc = L;
   if (HasFunctionName)
     setFunctionName(SL);
@@ -683,11 +684,12 @@
 
 PredefinedExpr *PredefinedExpr::Create(const ASTContext &Ctx, SourceLocation L,
                                        QualType FNTy, IdentKind IK,
+                                       bool TreatAsStringLiteral,
                                        StringLiteral *SL) {
   bool HasFunctionName = SL != nullptr;
   void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(HasFunctionName),
                            alignof(PredefinedExpr));
-  return new (Mem) PredefinedExpr(L, FNTy, IK, SL);
+  return new (Mem) PredefinedExpr(L, FNTy, IK, TreatAsStringLiteral, SL);
 }
 
 PredefinedExpr *PredefinedExpr::CreateEmpty(const ASTContext &Ctx,
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3582,7 +3582,8 @@
     }
   }
 
-  return PredefinedExpr::Create(Context, Loc, ResTy, IK, SL);
+  return PredefinedExpr::Create(Context, Loc, ResTy, IK, LangOpts.MicrosoftExt,
+                                SL);
 }
 
 ExprResult Sema::BuildSYCLUniqueStableNameExpr(SourceLocation OpLoc,
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -173,6 +173,8 @@
       E = GSE->getResultExpr();
     } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(E)) {
       E = CE->getChosenSubExpr();
+    } else if (PredefinedExpr *PE = dyn_cast<PredefinedExpr>(E)) {
+      E = PE->getFunctionName();
     } else {
       llvm_unreachable("unexpected expr in string literal init");
     }
diff --git a/clang/test/Sema/ms_predefined_expr.cpp b/clang/test/Sema/ms_predefined_expr.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/ms_predefined_expr.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 %s -fsyntax-only -Wmicrosoft -verify -fms-extensions
+// expected-no-diagnostics
+
+void f() {
+ const char a[] = __FUNCTION__;
+ const char b[] = __FUNCDNAME__;
+ const char c[] = __FUNCSIG__;
+ const char d[] = __func__;
+ const char e[] = __PRETTY_FUNCTION__;
+}