AMDGPU: Fix assert on ttmp registers

Use register class that does not include them when looking
for unallocated registers.

This is hit by the udiv v8i64 test in the opencl integer
conformance test, and takes a few seconds to compile in
a debug build so no test included.

llvm-svn: 269938

llvm/lib/Target/AMDGPU/SIFrameLowering.cpp

@@ -26,8 +26,8 @@ static bool hasOnlySGPRSpills(const SIMachineFunctionInfo *FuncInfo,
 }
 
 static ArrayRef<MCPhysReg> getAllSGPR128() {
-  return makeArrayRef(AMDGPU::SReg_128RegClass.begin(),
-                      AMDGPU::SReg_128RegClass.getNumRegs());
+  return makeArrayRef(AMDGPU::SGPR_128RegClass.begin(),
+                      AMDGPU::SGPR_128RegClass.getNumRegs());
 }
 
 static ArrayRef<MCPhysReg> getAllSGPRs() {