[all-commits] [llvm/llvm-project] 66e8cc: [ConstraintElim] Handle (X | Y) >s -1 as X >s -1 &...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 66e8cc5ec83d7ec5e506c53b11c1d22887c0c418
      https://github.com/llvm/llvm-project/commit/66e8cc5ec83d7ec5e506c53b11c1d22887c0c418
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2026-07-16 (Thu, 16 Jul 2026)

  Changed paths:
    M llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
    M llvm/test/Transforms/ConstraintElimination/or-non-negative.ll
    M llvm/test/Transforms/PhaseOrdering/constraint-eliminiation-interactions.ll

  Log Message:
  -----------
  [ConstraintElim] Handle (X | Y) >s -1 as X >s -1 && Y >s -1. (#209743)

InstCombine canonicalizes X >=s 0 && Y >=s 0 as (X | Y) >=s 0. Teach
ConstraintElimination to recover the signed-positive information by
looking through compares of binary ORs.

Alive2 Proof: https://alive2.llvm.org/ce/z/sqNF8M

Compile-time impact is neutral

https://llvm-compile-time-tracker.com/compare.php?from=88acd428fd72f44312408c3fb6165992fb3b043a&to=a2aa4cacb953b32d6319939b9aee3226a7294334&stat=instructions%3Au

PR: https://github.com/llvm/llvm-project/pull/209743



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