AMDGPU/SI: Handle s_setreg hazard in GCNHazardRecognizer

Reviewers: arsenm

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, llvm-commits, tony-tye

Differential Revision: https://reviews.llvm.org/D25528

llvm-svn: 285338

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 9e9f1904b26..100ea7e9a2d 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -76,6 +76,9 @@ GCNHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
   if (isSGetReg(MI->getOpcode()) && checkGetRegHazards(MI) > 0)
     return NoopHazard;
 
+  if (isSSetReg(MI->getOpcode()) && checkSetRegHazards(MI) > 0)
+    return NoopHazard;
+
   return NoHazard;
 }
 
@@ -99,6 +102,9 @@ unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
   if (isSGetReg(MI->getOpcode()))
     return std::max(0, checkGetRegHazards(MI));
 
+  if (isSSetReg(MI->getOpcode()))
+    return std::max(0, checkSetRegHazards(MI));
+
   return 0;
 }
 
@@ -331,3 +337,16 @@ int GCNHazardRecognizer::checkGetRegHazards(MachineInstr *GetRegInstr) {
 
   return GetRegWaitStates - WaitStatesNeeded;
 }
+
+int GCNHazardRecognizer::checkSetRegHazards(MachineInstr *SetRegInstr) {
+  const SIInstrInfo *TII = ST.getInstrInfo();
+  unsigned HWReg = getHWReg(TII, *SetRegInstr);
+
+  const int SetRegWaitStates =
+      ST.getGeneration() <= AMDGPUSubtarget::SEA_ISLANDS ? 1 : 2;
+  auto IsHazardFn = [TII, HWReg] (MachineInstr *MI) {
+    return HWReg == getHWReg(TII, *MI);
+  };
+  int WaitStatesNeeded = getWaitStatesSinceSetReg(IsHazardFn);
+  return SetRegWaitStates - WaitStatesNeeded;
+}