[PATCH] D134172: [InstCombine] Fold ult(add(x, -1), c) -> ule(x, c) iff x != 0 (PR57635)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
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Alive2: https://alive2.llvm.org/ce/z/sZ6wwS

As detailed on Issue #57635 and #37628 - for unsigned comparisons, we can compare prior to a loop counter decrement iff the counter is known never to be zero.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D134172

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
  llvm/test/Transforms/LoopUnroll/AArch64/runtime-unroll-generic.ll
  llvm/test/Transforms/LoopUnroll/runtime-unroll-remainder.ll
  llvm/test/Transforms/LoopVectorize/AArch64/intrinsiccost.ll
  llvm/test/Transforms/LoopVectorize/ARM/mve-reductions.ll
  llvm/test/Transforms/LoopVectorize/X86/float-induction-x86.ll
  llvm/test/Transforms/LoopVectorize/X86/intrinsiccost.ll
  llvm/test/Transforms/LoopVectorize/float-induction.ll
  llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll
  llvm/test/Transforms/LoopVectorize/induction.ll
  llvm/test/Transforms/LoopVectorize/runtime-check.ll

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