[PATCH] D54532: [InstructionSimplify] Add support for saturating add/sub

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
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Add support for saturating add/sub in InstructionSimplify. In particular, the following simplifications are supported:

- sat(X + 0) -> X
- sat(X + undef) -> X
- sat(X uadd MAX) -> MAX
- (and commutative variants)

- sat(X - 0) -> X
- sat(X - X) -> 0
- sat(X - undef) -> 0
- sat(undef - X) -> 0
- sat(0 usub X) -> 0
- sat(X usub MAX) -> 0


Repository:
  rL LLVM

https://reviews.llvm.org/D54532

Files:
  lib/Analysis/InstructionSimplify.cpp
  test/Transforms/InstSimplify/saturating-add-sub.ll

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