[all-commits] [llvm/llvm-project] 1e15ad: [AMDGPU] Add s_nop WaitStates between neighboring ...

[Austin Kerbow via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1e15adba62a9fbc00a9999d75818ef8b1fbb8cd7
      https://github.com/llvm/llvm-project/commit/1e15adba62a9fbc00a9999d75818ef8b1fbb8cd7
  Author: Austin Kerbow <Austin.Kerbow at amd.com>
  Date:   2022-03-23 (Wed, 23 Mar 2022)

  Changed paths:
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
    M llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
    A llvm/test/CodeGen/AMDGPU/neighboring-mfma-padding.mir

  Log Message:
  -----------
  [AMDGPU] Add s_nop WaitStates between neighboring mfma

In some cases padding bubbles between sequential MFMA instructions may
lead to increased inter-wave performance. Add option to request to pad
some portion of these stall cycles with s_nops.

Fixes: SWDEV-326925

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D121437