[all-commits] [llvm/llvm-project] 2b7b8b: [X86] Accept the canonical form of a sign bit test...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2b7b8bdc165a1f9fa933fe531d6a5b152d066297
      https://github.com/llvm/llvm-project/commit/2b7b8bdc165a1f9fa933fe531d6a5b152d066297
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2025-08-20 (Wed, 20 Aug 2025)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/vector-reduce-or-cmp.ll

  Log Message:
  -----------
  [X86] Accept the canonical form of a sign bit test in MatchVectorAllEqualTest. (#154421)

This function tries to look for (seteq (and (reduce_or), mask), 0). If
the mask is a sign bit, InstCombine will have turned it into (setgt
(reduce_or), -1). We should handle that case too.

I'm looking into adding the same canonicalization to SimplifySetCC and
this change is needed to prevent test regressions.



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