diff --git a/clang/lib/Basic/Targets/OSTargets.cpp b/clang/lib/Basic/Targets/OSTargets.cpp
--- a/clang/lib/Basic/Targets/OSTargets.cpp
+++ b/clang/lib/Basic/Targets/OSTargets.cpp
@@ -226,16 +226,6 @@
     }
   }
 
-  if (Opts.MicrosoftExt) {
-    Builder.defineMacro("_MSC_EXTENSIONS");
-
-    if (Opts.CPlusPlus11) {
-      Builder.defineMacro("_RVALUE_REFERENCES_V2_SUPPORTED");
-      Builder.defineMacro("_RVALUE_REFERENCES_SUPPORTED");
-      Builder.defineMacro("_NATIVE_NULLPTR_SUPPORTED");
-    }
-  }
-
   if (!Opts.MSVolatile)
     Builder.defineMacro("_ISO_VOLATILE");
 
@@ -264,6 +254,16 @@
   else if (Triple.isKnownWindowsMSVCEnvironment() ||
            (Triple.isWindowsItaniumEnvironment() && Opts.MSVCCompat))
     addVisualCDefines(Opts, Builder);
+
+  if (Opts.MicrosoftExt) {
+    Builder.defineMacro("_MSC_EXTENSIONS");
+
+    if (Opts.CPlusPlus11) {
+      Builder.defineMacro("_RVALUE_REFERENCES_V2_SUPPORTED");
+      Builder.defineMacro("_RVALUE_REFERENCES_SUPPORTED");
+      Builder.defineMacro("_NATIVE_NULLPTR_SUPPORTED");
+    }
+  }
 }
 
 } // namespace targets
diff --git a/clang/test/Preprocessor/predefined-win-macros.c b/clang/test/Preprocessor/predefined-win-macros.c
--- a/clang/test/Preprocessor/predefined-win-macros.c
+++ b/clang/test/Preprocessor/predefined-win-macros.c
@@ -120,6 +120,11 @@
 // CHECK-AMD64-MINGW: #define _WIN32 1
 // CHECK-AMD64-MINGW: #define _WIN64 1
 
+// RUN: %clang_cc1 -triple x86_64-windows-gnu %s -E -dM -o - -fms-extensions \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-AMD64-MINGW-MSE
+
+// CHECK-AMD64-MINGW-MSE: #define _MSC_EXTENSIONS 1
+
 // RUN: %clang_cc1 -triple aarch64-windows-gnu %s -E -dM -o - \
 // RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-ARM64-MINGW