Index: cfe/trunk/lib/Basic/Targets/AMDGPU.cpp
===================================================================
--- cfe/trunk/lib/Basic/Targets/AMDGPU.cpp
+++ cfe/trunk/lib/Basic/Targets/AMDGPU.cpp
@@ -131,9 +131,6 @@
 
   // XXX - What does the member GPU mean if device name string passed here?
   if (isAMDGCN(getTriple())) {
-    if (CPU.empty())
-      CPU = "gfx600";
-
     switch (llvm::AMDGPU::parseArchAMDGCN(CPU)) {
     case GK_GFX1012:
     case GK_GFX1011:
@@ -189,7 +186,7 @@
     case GK_GFX600:
       break;
     case GK_NONE:
-      return false;
+      break;
     default:
       llvm_unreachable("Unhandled GPU!");
     }
Index: cfe/trunk/test/Driver/amdgpu-mcpu.cl
===================================================================
--- cfe/trunk/test/Driver/amdgpu-mcpu.cl
+++ cfe/trunk/test/Driver/amdgpu-mcpu.cl
@@ -52,6 +52,7 @@
 // AMDGCN-based processors.
 //
 
+// RUN: %clang -### -target amdgcn %s 2>&1 | FileCheck --check-prefix=GCNDEFAULT %s
 // RUN: %clang -### -target amdgcn -mcpu=gfx600 %s 2>&1 | FileCheck --check-prefix=GFX600 %s
 // RUN: %clang -### -target amdgcn -mcpu=tahiti %s 2>&1 | FileCheck --check-prefix=TAHITI %s
 // RUN: %clang -### -target amdgcn -mcpu=gfx601 %s 2>&1 | FileCheck --check-prefix=GFX601 %s
@@ -90,6 +91,7 @@
 // RUN: %clang -### -target amdgcn -mcpu=gfx1011 %s 2>&1 | FileCheck --check-prefix=GFX1011 %s
 // RUN: %clang -### -target amdgcn -mcpu=gfx1012 %s 2>&1 | FileCheck --check-prefix=GFX1012 %s
 
+// GCNDEFAULT-NOT: -target-cpu
 // GFX600:    "-target-cpu" "gfx600"
 // TAHITI:    "-target-cpu" "tahiti"
 // GFX601:    "-target-cpu" "gfx601"