[PATCH] D60420: [ValueTracking] Use computeConstantRange() for signed add/sub overflow determination

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
nikic added reviewers: lebedev.ri, spatel.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

This is D59386 <https://reviews.llvm.org/D59386> for the signed case. The computeConstantRange() result is now intersected into the existing known bits information, allowing to detect additional no-overflow/always-overflow conditions (though the latter isn't used yet).

This (finally...) covers the motivating case from D59071 <https://reviews.llvm.org/D59071>.


Repository:
  rL LLVM

https://reviews.llvm.org/D60420

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Transforms/InstCombine/and2.ll
  llvm/test/Transforms/InstCombine/icmp-add.ll
  llvm/test/Transforms/InstCombine/sadd-with-overflow.ll
  llvm/test/Transforms/InstCombine/saturating-add-sub.ll
  llvm/test/Transforms/InstCombine/ssub-with-overflow.ll

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