small refactor

Author: mihajlovicana

llvm/lib/Target/AMDGPU/AMDGPUInsertDelayAlu.cpp

@@ -63,12 +63,8 @@ class AMDGPUInsertDelayAlu : public MachineFunctionPass {
 
   static bool instructionWaitsForSGPRWrites(const MachineInstr &MI) {
     // These instruction types wait for VA_SDST==0 before issuing.
-    // S_CBRANCH_EXECZ and S_CBRANCH_VCCZ are covered by SALU flag
-    const uint64_t VA_SDST_0 = SIInstrFlags::SALU | SIInstrFlags::EXP |
-                               SIInstrFlags::DS | SIInstrFlags::SMRD |
-                               SIInstrFlags::MIMG | SIInstrFlags::VIMAGE |
-                               SIInstrFlags::VSAMPLE;
-        
+    const uint64_t VA_SDST_0 = SIInstrFlags::SALU | SIInstrFlags::SMRD;
+
     if (MI.getDesc().TSFlags & VA_SDST_0)
       return true;
 
@@ -423,16 +419,13 @@ class AMDGPUInsertDelayAlu : public MachineFunctionPass {
         if (SII->isVALU(MI.getOpcode())) {
           for (const auto &Op : MI.defs()) {
             Register Reg = Op.getReg();
-            for (MCRegUnit Unit : TRI->regunits(Reg)) {
-              if (AMDGPU::isSGPR(Reg, TRI)) {
-                lastSGPRfromVALU = Unit;
-                break;
-              }
+            if (AMDGPU::isSGPR(Reg, TRI)) {
+              lastSGPRfromVALU = *(TRI->regunits(Reg).begin());
+              break;
             }
           }
         }
 
-
         if (Emit && !MI.isBundledWithPred()) {
           // TODO: For VALU->SALU delays should we use s_delay_alu or s_nop or
           // just ignore them?