Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -10124,7 +10124,8 @@
     // C++11 [dcl.constexpr]p1: The constexpr specifier shall be applied only to
     // the definition of a variable [...] or the declaration of a static data
     // member.
-    if (Var->isConstexpr() && !Var->isThisDeclarationADefinition()) {
+    if (Var->isConstexpr() && !Var->isThisDeclarationADefinition() &&
+        !Var->isThisDeclarationADemotedDefinition()) {
       if (Var->isStaticDataMember()) {
         // C++1z removes the relevant rule; the in-class declaration is always
         // a definition there.
Index: test/Modules/Inputs/merge-var-template-def/a.h
===================================================================
--- test/Modules/Inputs/merge-var-template-def/a.h
+++ test/Modules/Inputs/merge-var-template-def/a.h
@@ -3,4 +3,10 @@
 template<typename T> struct A { static bool b; };
 template<typename T> bool A<T>::b = false;
 template<typename T> void *get() { return &(A<T>::b); }
+
+template<typename T, T v>
+struct S { static constexpr T value = v; };
+template<typename T, T v>
+constexpr T S<T, v>::value;
+
 #endif
Index: test/Modules/Inputs/merge-var-template-def/b1.h
===================================================================
--- test/Modules/Inputs/merge-var-template-def/b1.h
+++ test/Modules/Inputs/merge-var-template-def/b1.h
@@ -3,5 +3,11 @@
 template<typename T> struct A { static bool b; };
 template<typename T> bool A<T>::b = false;
 template<typename T> void *get() { return &(A<T>::b); }
+
+template<typename T, T v>
+struct S { static constexpr T value = v; };
+template<typename T, T v>
+constexpr T S<T, v>::value;
+
 #include "a.h"
 #endif
Index: test/Modules/Inputs/merge-var-template-def/b2.h
===================================================================
--- test/Modules/Inputs/merge-var-template-def/b2.h
+++ test/Modules/Inputs/merge-var-template-def/b2.h
@@ -3,4 +3,10 @@
 template<typename T> struct A { static bool b; };
 template<typename T> bool A<T>::b = false;
 template<typename T> void *get() { return &(A<T>::b); }
+
+template<typename T, T v>
+struct S { static constexpr T value = v; };
+template<typename T, T v>
+constexpr T S<T, v>::value;
+
 #endif
Index: test/Modules/merge-var-template-def.cpp
===================================================================
--- test/Modules/merge-var-template-def.cpp
+++ test/Modules/merge-var-template-def.cpp
@@ -1,7 +1,10 @@
 // RUN: rm -rf %t
-// RUN: %clang_cc1 -I%S/Inputs/merge-var-template-def -verify -fmodules -Werror=undefined-internal -fmodules-local-submodule-visibility -fmodules-cache-path=%t -fimplicit-module-maps %s
+// RUN: %clang_cc1 -I%S/Inputs/merge-var-template-def -std=c++11 -verify %s
+// RUN: %clang_cc1 -I%S/Inputs/merge-var-template-def -std=c++11 -verify -fmodules -Werror=undefined-internal -fmodules-local-submodule-visibility -fmodules-cache-path=%t -fimplicit-module-maps %s
 // expected-no-diagnostics
 
 #include "b2.h"
 namespace { struct X; }
 void *x = get<X>();
+
+const bool *y = &S<bool, false>::value;