AMDGPU: Enable ConstrainCopy DAG mutation

This fixes a probably unintended divergence from the default
scheduler behavior.

llvm-svn: 287146
diff --git a/llvm/test/CodeGen/AMDGPU/or.ll b/llvm/test/CodeGen/AMDGPU/or.ll
index 3e25485..d0545e0 100644
--- a/llvm/test/CodeGen/AMDGPU/or.ll
+++ b/llvm/test/CodeGen/AMDGPU/or.ll
@@ -96,10 +96,10 @@
 ; SI-NOT: or_b32
 ; SI: s_or_b32 s[[VAL_LO]], s[[VAL_LO]], 63
 ; SI-NOT: or_b32
-; SI: v_mov_b32_e32 v[[VLO:[0-9]+]], s[[VAL_LO]]
-; SI-NOT: or_b32
 ; SI: v_mov_b32_e32 v[[VHI:[0-9]+]], s[[VAL_HI]]
 ; SI-NOT: or_b32
+; SI: v_mov_b32_e32 v[[VLO:[0-9]+]], s[[VAL_LO]]
+; SI-NOT: or_b32
 ; SI: buffer_store_dwordx2 v{{\[}}[[VLO]]:[[VHI]]{{\]}}
 define void @scalar_or_inline_imm_i64(i64 addrspace(1)* %out, i64 %a) {
   %or = or i64 %a, 63