[PATCH] D128155: [GuardWindening] Use freeze to widen using possible poison value.

[Serguei Katkov via Phabricator via llvm-commits]

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During the guard widening we can add a poison use in the first guard which
can result in undefined behavior which were not before due to this guard could
guards us from it.

To avoid this behavior we can use freeze instruction.


https://reviews.llvm.org/D128155

Files:
  llvm/lib/Transforms/Scalar/GuardWidening.cpp
  llvm/test/Transforms/GuardWidening/basic-loop.ll
  llvm/test/Transforms/GuardWidening/basic.ll
  llvm/test/Transforms/GuardWidening/basic_widenable_condition_guards.ll
  llvm/test/Transforms/GuardWidening/loop-schedule.ll
  llvm/test/Transforms/GuardWidening/mixed_guards.ll
  llvm/test/Transforms/GuardWidening/range-check-merging.ll

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