[all-commits] [llvm/llvm-project] 62cd07: [InstCombine] Canonicalize `sub mask, X -> ~X` whe...

[Yingwei Zheng via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 62cd07fb67c946d251a18d3a564b535553939c9a
      https://github.com/llvm/llvm-project/commit/62cd07fb67c946d251a18d3a564b535553939c9a
  Author: Yingwei Zheng <dtcxzyw2333 at gmail.com>
  Date:   2024-10-02 (Wed, 02 Oct 2024)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
    M llvm/test/Transforms/InstCombine/sub.ll
    M llvm/test/Transforms/PhaseOrdering/X86/vec-shift.ll

  Log Message:
  -----------
  [InstCombine] Canonicalize `sub mask, X -> ~X` when high bits are ignored (#110635)

Alive2: https://alive2.llvm.org/ce/z/NJgBPL

The motivating case of this patch is to emit `andn` on RISC-V with zbb
for expressions like `(sub 63, X) & 63`.



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