[PATCH] D79476: [AMDGPU] Don't implement GCNHazardRecognizer::PreEmitNoops(SUnit *)

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
foad added reviewers: hfinkel, rampitec, arsenm, tstellar, vpykhtin.
Herald added subscribers: llvm-commits, kerbowa, hiraditya, t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, jvesely, kzhuravl.
Herald added a project: LLVM.

When called from the post-RA scheduler, hazards have already been
handled by getHazardType returning NoopHazard, so PreEmitNoops always
returns zero. Remove it. NFC.

Historical note: PreEmitNoops was added to the hazard recognizer
interface as an optional feature to support dispatch group formation on
the POWER target:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20131202/197470.html
So it seems right that we shouldn't need to implement it.

We do still implement the other overload PreEmitNoops(MachineInstr *)
because that is used by the PostRAHazardRecognizer pass.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79476

Files:
  llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
  llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h


Index: llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
===================================================================
--- llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
+++ llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
@@ -105,7 +105,6 @@
   void EmitInstruction(MachineInstr *MI) override;
   HazardType getHazardType(SUnit *SU, int Stalls) override;
   void EmitNoop() override;
-  unsigned PreEmitNoops(SUnit *SU) override;
   unsigned PreEmitNoops(MachineInstr *) override;
   unsigned PreEmitNoopsCommon(MachineInstr *);
   void AdvanceCycle() override;
Index: llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -228,11 +228,6 @@
   CurrCycleInstr = nullptr;
 }
 
-unsigned GCNHazardRecognizer::PreEmitNoops(SUnit *SU) {
-  IsHazardRecognizerMode = false;
-  return PreEmitNoopsCommon(SU->getInstr());
-}
-
 unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
   IsHazardRecognizerMode = true;
   CurrCycleInstr = MI;


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