AMDGPU/SI: Move post regalloc run of SIShrinkInstructions

[• tstellarAMD]

Summary

Move to addPreEmitPass. This is so it runs after post-RA
scheduling so we can merge s_nops emitted by the scheduler
and hazard recognizer.

Patch by: Matt Arsenault

[• tstellarAMD]

Ping.

[arsenm]

I get verifier errors when I test this

[• tstellarAMD]

In D18600#408589, @arsenm wrote:

I get verifier errors when I test this

Which tests?

[arsenm]

r268095

lib/Target/AMDGPU/AMDGPUTargetMachine.cpp

 public:
   GCNPassConfig(TargetMachine *TM, PassManagerBase &PM)
     : AMDGPUPassConfig(TM, PM) { }
   bool addPreISel() override;
   bool addInstSelector() override;
   void addFastRegAlloc(FunctionPass *RegAllocPass) override;
   void addOptimizedRegAlloc(FunctionPass *RegAllocPass) override;
   void addPreRegAlloc() override;
-  void addPostRegAlloc() override;
   void addPreSched2() override;
   void addPreEmitPass() override;
 };
 
 } // End of anonymous namespace
 
 TargetIRAnalysis AMDGPUTargetMachine::getTargetIRAnalysis() {
   return TargetIRAnalysis([this](const Function &F) {
void GCNPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
   // We want to run this after LiveVariables is computed to avoid computing them
   // twice.
   // FIXME: We shouldn't disable the verifier here. r249087 introduced a failure
   // that needs to be fixed.
   insertPass(&LiveVariablesID, &SIFixSGPRLiveRangesID, /*VerifyAfter=*/false);
   TargetPassConfig::addOptimizedRegAlloc(RegAllocPass);
 }
 
-void GCNPassConfig::addPostRegAlloc() {
-  addPass(createSIShrinkInstructionsPass(), false);
-}
-
 void GCNPassConfig::addPreSched2() {
 }
 
 void GCNPassConfig::addPreEmitPass() {
   addPass(createSIInsertWaitsPass(), false);
+  addPass(createSIShrinkInstructionsPass());
   addPass(createSILowerControlFlowPass(), false);
   if (InsertNops) {
     addPass(createSIInsertNopsPass(), false);
   }
 }
 
 TargetPassConfig *GCNTargetMachine::createPassConfig(PassManagerBase &PM) {
   return new GCNPassConfig(this, PM);
 }