[all-commits] [llvm/llvm-project] f5199d: [AMDGPU] Revise handling of preexisting waitcnt

[Austin Kerbow via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f5199d7ae0edf47c41d7347aad18f893ad20f0b3
      https://github.com/llvm/llvm-project/commit/f5199d7ae0edf47c41d7347aad18f893ad20f0b3
  Author: Austin Kerbow <Austin.Kerbow at amd.com>
  Date:   2021-05-05 (Wed, 05 May 2021)

  Changed paths:
    M llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
    M llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.h
    M llvm/test/CodeGen/AMDGPU/GlobalISel/flat-scratch.ll
    M llvm/test/CodeGen/AMDGPU/atomicrmw-nand.ll
    M llvm/test/CodeGen/AMDGPU/flat-scratch.ll
    M llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
    M llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ds.gws.barrier.ll
    M llvm/test/CodeGen/AMDGPU/memory-legalizer-flat-agent.ll
    M llvm/test/CodeGen/AMDGPU/memory-legalizer-flat-system.ll
    M llvm/test/CodeGen/AMDGPU/memory-legalizer-flat-volatile.ll
    M llvm/test/CodeGen/AMDGPU/memory-legalizer-flat-workgroup.ll
    M llvm/test/CodeGen/AMDGPU/waitcnt-debug.mir
    A llvm/test/CodeGen/AMDGPU/waitcnt-preexisting-vscnt.mir
    M llvm/test/CodeGen/AMDGPU/waitcnt-preexisting.mir

  Log Message:
  -----------
  [AMDGPU] Revise handling of preexisting waitcnt

Preexisting waitcnt may not update the scoreboard if the instruction
being examined needed to wait on fewer counters than what was encoded in
the old waitcnt instruction. Fixing this results in the elimination of
some redudnat waitcnt.

These changes also enable combining consecutive waitcnt into a single
S_WAITCNT or S_WAITCNT_VSCNT instruction.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D100281