AMDGPU: Run SIFoldOperands after PeepholeOptimizer

PeepholeOptimizer cleans up redundant copies, which makes
the operand folding more effective.

shader-db stats:

Totals:
SGPRS: 34200 -> 34336 (0.40 %)
VGPRS: 22118 -> 21655 (-2.09 %)
Code Size: 632144 -> 633460 (0.21 %) bytes
LDS: 11 -> 11 (0.00 %) blocks
Scratch: 10240 -> 11264 (10.00 %) bytes per wave
Max Waves: 8822 -> 8918 (1.09 %)
Wait states: 0 -> 0 (0.00 %)

Totals from affected shaders:
SGPRS: 7704 -> 7840 (1.77 %)
VGPRS: 5169 -> 4706 (-8.96 %)
Code Size: 234444 -> 235760 (0.56 %) bytes
LDS: 2 -> 2 (0.00 %) blocks
Scratch: 0 -> 1024 (0.00 %) bytes per wave
Max Waves: 1188 -> 1284 (8.08 %)
Wait states: 0 -> 0 (0.00 %)

Increases:
SGPRS: 35 (0.01 %)
VGPRS: 1 (0.00 %)
Code Size: 59 (0.02 %)
LDS: 0 (0.00 %)
Scratch: 1 (0.00 %)
Max Waves: 48 (0.02 %)
Wait states: 0 (0.00 %)

Decreases:
SGPRS: 26 (0.01 %)
VGPRS: 54 (0.02 %)
Code Size: 68 (0.03 %)
LDS: 0 (0.00 %)
Scratch: 0 (0.00 %)
Max Waves: 4 (0.00 %)
Wait states: 0 (0.00 %)

llvm-svn: 266378
diff --git a/llvm/test/CodeGen/AMDGPU/fma.ll b/llvm/test/CodeGen/AMDGPU/fma.ll
index d6024aa..d04a594 100644
--- a/llvm/test/CodeGen/AMDGPU/fma.ll
+++ b/llvm/test/CodeGen/AMDGPU/fma.ll
@@ -61,7 +61,7 @@
 }
 
 ; FUNC-LABEL: @fma_commute_mul_inline_imm_f32
-; SI: v_fma_f32 {{v[0-9]+}}, 2.0, {{v[0-9]+}}, {{v[0-9]+}}
+; SI: v_fma_f32 {{v[0-9]+}}, {{v[0-9]+}}, 2.0, {{v[0-9]+}}
 define void @fma_commute_mul_inline_imm_f32(float addrspace(1)* noalias %out, float addrspace(1)* noalias %in.a, float addrspace(1)* noalias %in.b) nounwind {
   %tid = tail call i32 @llvm.r600.read.tidig.x() nounwind readnone
   %in.a.gep = getelementptr float, float addrspace(1)* %in.a, i32 %tid