[PATCH] D113510: [InstCombine] Strip offset when folding and/or of icmps

[Nikita Popov via Phabricator via llvm-commits]

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When folding and/or of icmps, look through add of a constant and adjust the icmp range instead. Effectively, this decomposes `X + C1 < C2` style range checks back into a normal range. This allows us to fold comparisons involving two range checks or one range check and some other condition. We had a fold for a really specific case of this (or of range check and eq, and only one one side!) while this handles it in fully generality.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D113510

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/and-or-icmps.ll
  llvm/test/Transforms/InstCombine/or.ll
  llvm/test/Transforms/InstCombine/signed-truncation-check.ll

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