[all-commits] [llvm/llvm-project] 947011: [AMDGPU] Mark workitem IDs uniform in more cases (...

[Krzysztof Drewniak via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9470113495a79ee4f857b566c60a0adcd48c9d2a
      https://github.com/llvm/llvm-project/commit/9470113495a79ee4f857b566c60a0adcd48c9d2a
  Author: Krzysztof Drewniak <Krzysztof.Drewniak at amd.com>
  Date:   2025-08-29 (Fri, 29 Aug 2025)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
    M llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
    M llvm/test/Analysis/UniformityAnalysis/AMDGPU/workitem-intrinsics.ll
    M llvm/test/CodeGen/AMDGPU/uniform-load-from-tid.ll

  Log Message:
  -----------
  [AMDGPU] Mark workitem IDs uniform in more cases (#152581)

This fixes an old FIXME, where (workitem ID X) / (wavefrront size) would
never be marked uniform if it was possible that there would be Y and Z
dimensions. Now, so long as the required size of the X dimension is a
power of 2, dividing that dimension by the wavefront size creates a
uniform value.

Furthermore, if the required launch size of the X dimension is a power
of 2 that's at least the wavefront size, the Y and Z workitem IDs are
now marked uniform.

---------

Co-authored-by: Matt Arsenault <arsenm2 at gmail.com>



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