[all-commits] [llvm/llvm-project] cff226: [ConstraintElim] Fold sadd.with.overflow with a co...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: cff226a5716e4bc3589d4869066ea6687ed142ce
      https://github.com/llvm/llvm-project/commit/cff226a5716e4bc3589d4869066ea6687ed142ce
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2026-09-13 (Sun, 13 Sep 2026)

  Changed paths:
    M llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
    M llvm/test/Transforms/ConstraintElimination/sadd-with-overflow.ll

  Log Message:
  -----------
  [ConstraintElim] Fold sadd.with.overflow with a constant op. (#223239)

Generalize the overflow-math simplification to also allow simplifying
sadd.with.overflow if the second operand is constant, using
makeGuaranteedNoWrapRegion.

Note that this partially overlaps with the flag strengthening logic.
I'll share a patch soon to try to unify the code more.

No improvements in llvm-opt-benchmarks-nightly. It improves end-to-end
optimizations for Swift (which emits a lot of checked arithmetic) and
also Clang + UBsan.

An end-to-end improvement with overflow intrinsics is
https://llvm.godbolt.org/z/6nrj7aodd.

PR: https://github.com/llvm/llvm-project/pull/223239



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