[PATCH] D143726: [LoopInstSimplify] Simplify (X < A && X < B) into (X < MIN(A, B)) if MIN(A, B) is loop-invariant

[Max Kazantsev via Phabricator via llvm-commits]

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We don't do this transform in InstCombine in general case for arbitrary values, because cost of
AND and 2 ICMP's isn't higher than of MIN and ICMP. However, LoopInstSimplify also has a notion
about the loop structure. This transform becomes profitable if `A` and `B` are loop-invariant and
`X` is not: by doing this, we can compute min outside the loop.


https://reviews.llvm.org/D143726

Files:
  llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
  llvm/test/Transforms/LoopInstSimplify/loop_invariant.ll

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