[PATCH] D78582: [InstCombine] substitute equivalent constant to reduce logic-of-icmps

[Sanjay Patel via Phabricator via llvm-commits]

spatel created this revision.
spatel added reviewers: aqjune, lebedev.ri, nikic.
Herald added subscribers: hiraditya, mcrosier.

(X == C) && (Y Pred1 X) --> (X == C) && (Y Pred1 C)
(X != C) || (Y Pred1 X) --> (X != C) || (Y Pred1 C)

This is not a complete alternate to D78430 <https://reviews.llvm.org/D78430>, but it is a more general transform that gets us most of the expected simplifications and several other improvements. It's a smaller patch too, so hopefully, less chance to go wrong assuming the underlying logic is correct:
http://volta.cs.utah.edu:8080/z/5gxjjc

PR45618:
https://bugs.llvm.org/show_bug.cgi?id=45618


https://reviews.llvm.org/D78582

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/and-or-icmp-min-max.ll
  llvm/test/Transforms/InstCombine/and-or-icmp-nullptr.ll
  llvm/test/Transforms/InstCombine/and-or-icmps.ll

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