Enable FeatureFlatForGlobal on Volcanic Islands

This switches to the workaround that HSA defaults to
for the mesa path.

This should be applied to the 4.0 branch.

Patch by Vedran Miletić <vedran@miletic.net>

llvm-svn: 292982
diff --git a/llvm/test/CodeGen/AMDGPU/32-bit-local-address-space.ll b/llvm/test/CodeGen/AMDGPU/32-bit-local-address-space.ll
index 6495a14..edad18e 100644
--- a/llvm/test/CodeGen/AMDGPU/32-bit-local-address-space.ll
+++ b/llvm/test/CodeGen/AMDGPU/32-bit-local-address-space.ll
@@ -1,5 +1,5 @@
 ; RUN: llc -march=amdgcn -mcpu=bonaire -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
-; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 
 ; On Southern Islands GPUs the local address space(3) uses 32-bit pointers and
 ; the global address space(1) uses 64-bit pointers.  These tests check to make sure