Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -6603,7 +6603,8 @@
       }
       // OpenCL v1.1 s6.5.2 and s6.5.3 no local or constant variables
       // in functions.
-      if (T.getAddressSpace() == LangAS::opencl_constant ||
+      if ((T.getAddressSpace() == LangAS::opencl_constant &&
+           !NewVD->isLocalExternDecl()) ||
           T.getAddressSpace() == LangAS::opencl_local) {
         FunctionDecl *FD = getCurFunctionDecl();
         if (FD && !FD->hasAttr<OpenCLKernelAttr>()) {
Index: test/SemaOpenCL/extern.cl
===================================================================
--- test/SemaOpenCL/extern.cl
+++ test/SemaOpenCL/extern.cl
@@ -7,3 +7,10 @@
 kernel void test(global float* buf) {
   buf[0] += foo;
 }
+
+void test2(global float* buf) {
+// CHECK: @bar = external addrspace(3) constant [0 x float]
+  extern constant float bar[];
+  buf[0] += bar[0];
+}
+