[PATCH] D126687: [InstCombine] Fix inbounds preservation when swapping GEPs (PR44206)

[Nikita Popov via Phabricator via llvm-commits]

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When reassociating GEPs, we can only keep inbounds if both original GEPs were inbounds, and their offsets have the same sign. For the sake of simplicity I only handle the case where both offsets are non-negative here.

It would probably be fine to just not preserve inbounds at all here, but as I don't see a compile-time impact for adding the isKnownNonNegative() calls I went with this more conservative approach.

Fixes https://github.com/llvm/llvm-project/issues/44206.


https://reviews.llvm.org/D126687

Files:
  llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
  llvm/test/Transforms/InstCombine/gep-combine-loop-invariant.ll
  llvm/test/Transforms/LoopVectorize/ARM/mve-reductions.ll
  llvm/test/Transforms/LoopVectorize/X86/x86-interleaved-accesses-masked-group.ll
  llvm/test/Transforms/LoopVectorize/X86/x86-interleaved-store-accesses-with-gaps.ll
  llvm/test/Transforms/LoopVectorize/consecutive-ptr-uniforms.ll
  llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll

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