diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -149,7 +149,7 @@
   // In Microsoft mode, downgrade this to a warning.
   unsigned DiagID = diag::err_incomplete_in_exception_spec;
   bool ReturnValueOnError = true;
-  if (getLangOpts().MicrosoftExt) {
+  if (getLangOpts().MSVCCompat) {
     DiagID = diag::ext_incomplete_in_exception_spec;
     ReturnValueOnError = false;
   }
@@ -282,7 +282,7 @@
 
   unsigned DiagID = diag::err_mismatched_exception_spec;
   bool ReturnValueOnError = true;
-  if (getLangOpts().MicrosoftExt) {
+  if (getLangOpts().MSVCCompat) {
     DiagID = diag::ext_mismatched_exception_spec;
     ReturnValueOnError = false;
   }
@@ -371,7 +371,7 @@
         NewProto->getExtProtoInfo().withExceptionSpec(ESI)));
   }
 
-  if (getLangOpts().MicrosoftExt && ESI.Type != EST_DependentNoexcept) {
+  if (getLangOpts().MSVCCompat && ESI.Type != EST_DependentNoexcept) {
     // Allow missing exception specifications in redeclarations as an extension.
     DiagID = diag::ext_ms_missing_exception_specification;
     ReturnValueOnError = false;
@@ -473,14 +473,14 @@
     return false;
 
   unsigned DiagID = diag::err_mismatched_exception_spec;
-  if (getLangOpts().MicrosoftExt)
+  if (getLangOpts().MSVCCompat)
     DiagID = diag::ext_mismatched_exception_spec;
   bool Result = CheckEquivalentExceptionSpecImpl(
       *this, PDiag(DiagID), PDiag(diag::note_previous_declaration),
       Old, OldLoc, New, NewLoc);
 
   // In Microsoft mode, mismatching exception specifications just cause a warning.
-  if (getLangOpts().MicrosoftExt)
+  if (getLangOpts().MSVCCompat)
     return false;
   return Result;
 }
@@ -959,7 +959,7 @@
   }
 
   unsigned DiagID = diag::err_override_exception_spec;
-  if (getLangOpts().MicrosoftExt)
+  if (getLangOpts().MSVCCompat)
     DiagID = diag::ext_override_exception_spec;
   return CheckExceptionSpecSubset(PDiag(DiagID),
                                   PDiag(diag::err_deep_exception_specs_differ),
diff --git a/clang/test/CodeGenCXX/pr18661.cpp b/clang/test/CodeGenCXX/pr18661.cpp
--- a/clang/test/CodeGenCXX/pr18661.cpp
+++ b/clang/test/CodeGenCXX/pr18661.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -triple %itanium_abi_triple -fcxx-exceptions -fms-extensions -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple %itanium_abi_triple -fcxx-exceptions -fms-compatibility -emit-llvm -o - | FileCheck %s
 
 extern "C" {
   void f();
diff --git a/clang/test/SemaCXX/MicrosoftCompatibility.cpp b/clang/test/SemaCXX/MicrosoftCompatibility.cpp
--- a/clang/test/SemaCXX/MicrosoftCompatibility.cpp
+++ b/clang/test/SemaCXX/MicrosoftCompatibility.cpp
@@ -322,3 +322,47 @@
 void instantiate() { ConfuseLookup<int>::m_val::ms_test = 1; }
 }
 
+
+// Microsoft doesn't validate exception specification.
+namespace microsoft_exception_spec {
+
+void foo(); // expected-note {{previous declaration}}
+void foo() throw(); // expected-warning {{exception specification in declaration does not match previous declaration}}
+
+void r6() throw(...); // expected-note {{previous declaration}}
+void r6() throw(int); // expected-warning {{exception specification in declaration does not match previous declaration}}
+
+struct Base {
+  virtual void f2();
+  virtual void f3() throw(...);
+};
+
+struct Derived : Base {
+  virtual void f2() throw(...);
+  virtual void f3();
+};
+
+class A {
+  virtual ~A() throw();
+#if __cplusplus <= 199711L
+  // expected-note@-2 {{overridden virtual function is here}}
+#endif
+};
+
+class B : public A {
+  virtual ~B();
+#if __cplusplus <= 199711L
+  // expected-warning@-2 {{exception specification of overriding function is more lax than base version}}
+#endif
+};
+
+}
+
+namespace PR25265 {
+struct S {
+  int fn() throw(); // expected-note {{previous declaration is here}}
+};
+
+int S::fn() { return 0; } // expected-warning {{is missing exception specification}}
+}
+
diff --git a/clang/test/SemaCXX/MicrosoftExtensions.cpp b/clang/test/SemaCXX/MicrosoftExtensions.cpp
--- a/clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ b/clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -6,41 +6,6 @@
 
 #if TEST1
 
-// Microsoft doesn't validate exception specification.
-namespace microsoft_exception_spec {
-
-void foo(); // expected-note {{previous declaration}}
-void foo() throw(); // expected-warning {{exception specification in declaration does not match previous declaration}}
-
-void r6() throw(...); // expected-note {{previous declaration}}
-void r6() throw(int); // expected-warning {{exception specification in declaration does not match previous declaration}}
-
-struct Base {
-  virtual void f2();
-  virtual void f3() throw(...);
-};
-
-struct Derived : Base {
-  virtual void f2() throw(...);
-  virtual void f3();
-};
-
-class A {
-  virtual ~A() throw();
-#if __cplusplus <= 199711L
-  // expected-note@-2 {{overridden virtual function is here}}
-#endif
-};
-
-class B : public A {
-  virtual ~B();
-#if __cplusplus <= 199711L
-  // expected-warning@-2 {{exception specification of overriding function is more lax than base version}}
-#endif
-};
-
-}
-
 // MSVC allows type definition in anonymous union and struct
 struct A
 {
@@ -495,14 +460,6 @@
 };
 }
 
-namespace PR25265 {
-struct S {
-  int fn() throw(); // expected-note {{previous declaration is here}}
-};
-
-int S::fn() { return 0; } // expected-warning {{is missing exception specification}}
-}
-
 class PR34109_class {
   PR34109_class() {}
   virtual ~PR34109_class() {}
diff --git a/clang/test/SemaCXX/ms-exception-spec.cpp b/clang/test/SemaCXX/ms-exception-spec.cpp
--- a/clang/test/SemaCXX/ms-exception-spec.cpp
+++ b/clang/test/SemaCXX/ms-exception-spec.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -fsyntax-only -verify -fms-extensions -fexceptions -fcxx-exceptions
+// RUN: %clang_cc1 %s -fsyntax-only -verify -fms-compatibility -fexceptions -fcxx-exceptions
 
 void f() throw(...) { }