diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 5897f2c48569..2803310c3256 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1275,13 +1275,8 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
       if (Var->getTLSKind())
         return false;
 
-      // Check if this is a dllimport variable.  Fail evaluation if we care
-      // about side effects; a dllimport variable rarely acts like a constant
-      // except in places like template arguments.  It never acts like a
-      // constant in C.
-      if ((!Info.getLangOpts().CPlusPlus ||
-           !Info.keepEvaluatingAfterSideEffect()) &&
-          Var->hasAttr<DLLImportAttr>())
+      // A dllimport variable never acts like a constant.
+      if (Var->hasAttr<DLLImportAttr>())
         return false;
     }
     if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
@@ -1295,9 +1290,7 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
       // The C language has no notion of ODR; furthermore, it has no notion of
       // dynamic initialization.  This means that we are permitted to
       // perform initialization with the address of the thunk.
-      if (Info.getLangOpts().CPlusPlus &&
-          !Info.keepEvaluatingAfterSideEffect() &&
-          FD->hasAttr<DLLImportAttr>())
+      if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
         return false;
     }
   }
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 84c58d12ea8e..00d93f852808 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -4193,7 +4193,7 @@ isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
   if (Arg->isValueDependent() || Arg->isTypeDependent())
     return NPV_NotNullPointer;
   
-  if (!S.getLangOpts().CPlusPlus11)
+  if (!S.getLangOpts().CPlusPlus11 || S.getLangOpts().MSVCCompat)
     return NPV_NotNullPointer;
   
   // Determine whether we have a constant expression.
diff --git a/clang/test/CodeGenCXX/dllimport.cpp b/clang/test/CodeGenCXX/dllimport.cpp
index 63b119277eca..d15eea24f2f5 100644
--- a/clang/test/CodeGenCXX/dllimport.cpp
+++ b/clang/test/CodeGenCXX/dllimport.cpp
@@ -94,6 +94,14 @@ inline int __declspec(dllimport) inlineStaticLocalsFunc() {
 };
 USE(inlineStaticLocalsFunc);
 
+// The address of a dllimport global cannot be used in constant initialization.
+// M32-DAG: @"\01?arr@?0??initializationFunc@@YAPAHXZ@4QBQAHB" = internal global [1 x i32*] zeroinitializer
+// GNU-DAG: @_ZZ18initializationFuncvE3arr = internal global [1 x i32*] zeroinitializer
+int *initializationFunc() {
+  static int *const arr[] = {&ExternGlobalDecl};
+  return arr[0];
+}
+USE(initializationFunc);
 
 
 //===----------------------------------------------------------------------===//
diff --git a/clang/test/Parser/MicrosoftExtensions.cpp b/clang/test/Parser/MicrosoftExtensions.cpp
index 7f3ef6d903c4..076de7cd785c 100644
--- a/clang/test/Parser/MicrosoftExtensions.cpp
+++ b/clang/test/Parser/MicrosoftExtensions.cpp
@@ -118,7 +118,7 @@ typedef COM_CLASS_TEMPLATE_REF<struct_with_uuid, __uuidof(struct_with_uuid)> COM
 
 COM_CLASS_TEMPLATE_REF<int, __uuidof(struct_with_uuid)> good_template_arg;
 
-COM_CLASS_TEMPLATE<int, __uuidof(struct_with_uuid)> bad_template_arg; // expected-error {{non-type template argument of type 'const _GUID' is not a constant expression}}
+COM_CLASS_TEMPLATE<int, __uuidof(struct_with_uuid)> bad_template_arg; // expected-error {{non-type template argument of type 'const _GUID' cannot be converted to a value of type 'const GUID *' (aka 'const _GUID *')}}
 
 namespace PR16911 {
 struct __declspec(uuid("{12345678-1234-1234-1234-1234567890aB}")) uuid;
diff --git a/clang/test/SemaCXX/PR19955.cpp b/clang/test/SemaCXX/PR19955.cpp
index 4596e5a459e4..fb1d74631b2b 100644
--- a/clang/test/SemaCXX/PR19955.cpp
+++ b/clang/test/SemaCXX/PR19955.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple i686-win32 -verify -std=c++11 %s
+// RUN: %clang_cc1 -triple i686-win32 -fms-compatibility -verify -std=c++11 %s
 
 extern int __attribute__((dllimport)) var;
 constexpr int *varp = &var; // expected-error {{must be initialized by a constant expression}}