[all-commits] [llvm/llvm-project] 9ebaeb: DAG: Avoid breaking legal vector_shuffle with mult...

[Matt Arsenault via All-commits]

  Branch: refs/heads/users/arsenm/dag/avoid-breaking-multi-use-legal-shuffle-after-legalize
  Home:   https://github.com/llvm/llvm-project
  Commit: 9ebaeb13b73288d0805e0d91c43f28d6660ee365
      https://github.com/llvm/llvm-project/commit/9ebaeb13b73288d0805e0d91c43f28d6660ee365
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2025-01-28 (Tue, 28 Jan 2025)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v3f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v4f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v2i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v3i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v4i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v3p3.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v4p3.ll

  Log Message:
  -----------
  DAG: Avoid breaking legal vector_shuffle with multiple uses

Previously this combine would undo AMDGPU's new custom legalization of
wide vector shuffles into 2 element pieces. The comment also
states that this combine is only done before legalization,
but the case with a build_vector source was unconditional.

We probably don't want to do this if the multiple uses are full
scalarization of the vector, but this seems to work well enough.
Scalarizing extracts should have folded out pre-legalize.


  Commit: 30ea5347ae4a2ff0303213bef00081504c2a810f
      https://github.com/llvm/llvm-project/commit/30ea5347ae4a2ff0303213bef00081504c2a810f
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2025-01-28 (Tue, 28 Jan 2025)

  Changed paths:
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v3f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v4f32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v2i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v3i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4i32.v4i32.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v3p3.ll
    M llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v4p3.ll

  Log Message:
  -----------
  Update tests for base commit changes


Compare: https://github.com/llvm/llvm-project/compare/3f44d3bdab67...30ea5347ae4a

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