[llvm] 29067aa - [AMDGPU] Don't implement GCNHazardRecognizer::PreEmitNoops(SUnit *)

[Jay Foad via llvm-commits]

Author: Jay Foad
Date: 2020-05-06T16:11:19+01:00
New Revision: 29067aac46d4f53f75c2d7e07e1afb7cb36212be

URL: https://github.com/llvm/llvm-project/commit/29067aac46d4f53f75c2d7e07e1afb7cb36212be
DIFF: https://github.com/llvm/llvm-project/commit/29067aac46d4f53f75c2d7e07e1afb7cb36212be.diff

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

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.

Differential Revision: https://reviews.llvm.org/D79476

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 02a44f929217..8482dbfec250 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -228,11 +228,6 @@ void GCNHazardRecognizer::processBundle() {
   CurrCycleInstr = nullptr;
 }
 
-unsigned GCNHazardRecognizer::PreEmitNoops(SUnit *SU) {
-  IsHazardRecognizerMode = false;
-  return PreEmitNoopsCommon(SU->getInstr());
-}
-
 unsigned GCNHazardRecognizer::PreEmitNoops(MachineInstr *MI) {
   IsHazardRecognizerMode = true;
   CurrCycleInstr = MI;

diff  --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
index 6aa2e70dfbfb..cd17f2755bd1 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
@@ -105,7 +105,6 @@ class GCNHazardRecognizer final : public ScheduleHazardRecognizer {
   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;