R600/SI: Add a stub GCNTargetMachine

This is equivalent to the AMDGPUTargetMachine now, but it is the
starting point for separating R600 and GCN functionality into separate
targets.

It is recommened that users start using the gcn triple for GCN-based
GPUs, because using the r600 triple for these GPUs will be deprecated in
the future.

llvm-svn: 225277
diff --git a/llvm/test/CodeGen/R600/32-bit-local-address-space.ll b/llvm/test/CodeGen/R600/32-bit-local-address-space.ll
index 4ff2762..6ab0c08 100644
--- a/llvm/test/CodeGen/R600/32-bit-local-address-space.ll
+++ b/llvm/test/CodeGen/R600/32-bit-local-address-space.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=r600 -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -mcpu=verde -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