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/local-64.ll b/llvm/test/CodeGen/AMDGPU/local-64.ll
index 5cabd4d..a7cee43 100644
--- a/llvm/test/CodeGen/AMDGPU/local-64.ll
+++ b/llvm/test/CodeGen/AMDGPU/local-64.ll
@@ -1,6 +1,6 @@
-; RUN: llc -march=amdgcn -mcpu=SI -verify-machineinstrs< %s | FileCheck --check-prefix=SI --check-prefix=BOTH %s
+; RUN: llc -march=amdgcn -verify-machineinstrs< %s | FileCheck --check-prefix=SI --check-prefix=BOTH %s
 ; RUN: llc -march=amdgcn -mcpu=bonaire -verify-machineinstrs< %s | FileCheck --check-prefix=CI --check-prefix=BOTH %s
-; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs< %s | FileCheck --check-prefix=CI --check-prefix=BOTH %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-flat-for-global -verify-machineinstrs< %s | FileCheck --check-prefix=CI --check-prefix=BOTH %s
 
 ; BOTH-LABEL: {{^}}local_i32_load
 ; BOTH: ds_read_b32 [[REG:v[0-9]+]], v{{[0-9]+}} offset:28