Index: lib/Sema/SemaOverload.cpp
===================================================================
--- lib/Sema/SemaOverload.cpp
+++ lib/Sema/SemaOverload.cpp
@@ -1129,7 +1129,10 @@
     // Don't allow mixing of HD with other kinds. This guarantees that
     // we have only one viable function with this signature on any
     // side of CUDA compilation .
-    if ((NewTarget == CFT_HostDevice) || (OldTarget == CFT_HostDevice))
+    // __global__ functions can't be overloaded based on attribute
+    // difference because, like HD, they also exist on both sides.
+    if ((NewTarget == CFT_HostDevice) || (OldTarget == CFT_HostDevice) ||
+        (NewTarget == CFT_Global) || (OldTarget == CFT_Global))
       return false;
 
     // Allow overloading of functions with same signature, but
Index: test/SemaCUDA/function-overload.cu
===================================================================
--- test/SemaCUDA/function-overload.cu
+++ test/SemaCUDA/function-overload.cu
@@ -302,3 +302,13 @@
   __host__ __device__ void operator delete(void *ptr) {} // expected-note {{previous declaration is here}}
   __device__ void operator delete(void *ptr) {} // expected-error {{class member cannot be redeclared}}
 };
+
+// __global__ functions can't be overloaded based on attribute
+// difference.
+struct G {
+  friend void friend_of_g(G &arg);
+private:
+  int x;
+};
+__global__ void friend_of_g(G &arg) { int x = arg.x; } // expected-note {{previous definition is here}}
+void friend_of_g(G &arg) { int x = arg.x; } // expected-error {{redefinition of 'friend_of_g'}}