[all-commits] [llvm/llvm-project] fa6e57: DAG: Use poison for some load/store offsets in leg...

[Matt Arsenault via All-commits]

  Branch: refs/heads/users/arsenm/dag/legalizer-use-poison-load-store-offsets
  Home:   https://github.com/llvm/llvm-project
  Commit: fa6e57b99e07eafdb558bd6b6a90762b6300097c
      https://github.com/llvm/llvm-project/commit/fa6e57b99e07eafdb558bd6b6a90762b6300097c
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2026-07-31 (Fri, 31 Jul 2026)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    M llvm/lib/Target/ARM/ARMISelLowering.cpp
    M llvm/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/lib/Target/X86/X86ISelLowering.cpp

  Log Message:
  -----------
  DAG: Use poison for some load/store offsets in legalizer

Unindexed load/store offsets are a don't-care operand that must be poison
rather than undef now that poison is legal. Convert the remaining producers
that build the offset with getUNDEF (in SelectionDAGBuilder and the ARM,
Hexagon, RISCV, and X86 lowerings) to getPOISON, and strengthen the offset
asserts in the SelectionDAG memory-node builders to require POISON exactly
instead of accepting any undef-or-poison value.

Co-Authored-By: Claude (Claude-Opus-4.8) <noreply at anthropic.com>



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