[all-commits] [llvm/llvm-project] 29067a: [AMDGPU] Don't implement GCNHazardRecognizer::PreE...

[jayfoad via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 29067aac46d4f53f75c2d7e07e1afb7cb36212be
      https://github.com/llvm/llvm-project/commit/29067aac46d4f53f75c2d7e07e1afb7cb36212be
  Author: Jay Foad <jay.foad at amd.com>
  Date:   2020-05-06 (Wed, 06 May 2020)

  Changed paths:
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h

  Log Message:
  -----------
  [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