1 files changed, 16 insertions, 5 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 2a9f76212b9..aa2ebbe2852 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -83,6 +83,7 @@ extern "C" void LLVMInitializeAMDGPUTarget() {
   initializeSILowerControlFlowPass(*PR);
   initializeSIInsertSkipsPass(*PR);
   initializeSIDebuggerInsertNopsPass(*PR);
+  initializeSIOptimizeExecMaskingPass(*PR);
 }
 
 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
@@ -333,6 +334,7 @@ public:
   void addFastRegAlloc(FunctionPass *RegAllocPass) override;
   void addOptimizedRegAlloc(FunctionPass *RegAllocPass) override;
   void addPreRegAlloc() override;
+  void addPostRegAlloc() override;
   void addPreSched2() override;
   void addPreEmitPass() override;
 };
@@ -548,7 +550,6 @@ bool GCNPassConfig::addGlobalInstructionSelect() {
 #endif
 
 void GCNPassConfig::addPreRegAlloc() {
-
   addPass(createSIShrinkInstructionsPass());
   addPass(createSIWholeQuadModePass());
 }
@@ -556,7 +557,11 @@ void GCNPassConfig::addPreRegAlloc() {
 void GCNPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
   // FIXME: We have to disable the verifier here because of PHIElimination +
   // TwoAddressInstructions disabling it.
-  insertPass(&TwoAddressInstructionPassID, &SILowerControlFlowID, false);
+
+  // This must be run immediately after phi elimination and before
+  // TwoAddressInstructions, otherwise the processing of the tied operand of
+  // SI_ELSE will introduce a copy of the tied operand source after the else.
+  insertPass(&PHIEliminationID, &SILowerControlFlowID, false);
 
   TargetPassConfig::addFastRegAlloc(RegAllocPass);
 }
@@ -566,13 +571,19 @@ void GCNPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
   // passes might recompute live intervals.
   insertPass(&MachineSchedulerID, &SIFixControlFlowLiveIntervalsID);
 
-  // TODO: It might be better to run this right after phi elimination, but for
-  // now that would require not running the verifier.
-  insertPass(&RenameIndependentSubregsID, &SILowerControlFlowID);
+  // This must be run immediately after phi elimination and before
+  // TwoAddressInstructions, otherwise the processing of the tied operand of
+  // SI_ELSE will introduce a copy of the tied operand source after the else.
+  insertPass(&PHIEliminationID, &SILowerControlFlowID, false);
 
   TargetPassConfig::addOptimizedRegAlloc(RegAllocPass);
 }
 
+void GCNPassConfig::addPostRegAlloc() {
+  addPass(&SIOptimizeExecMaskingID);
+  TargetPassConfig::addPostRegAlloc();
+}
+
 void GCNPassConfig::addPreSched2() {
 }