[PATCH] D50301: [InstCombine] De Morgan: sink 'not' into 'xor' (PR38446)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: spatel, craig.topper.

https://rise4fun.com/Alive/IT3

Comes up in the [most ugliest]  `signed int` -> `signed char`  case of
`-fsanitize=implicit-conversion` (https://reviews.llvm.org/D50250)
Previously, we were stuck with `not`: F6867736: old.ll <https://reviews.llvm.org/F6867736>
But now we are able to completely get rid of it: F6867737: new.ll <https://reviews.llvm.org/F6867737>
(FIXME: why are we loosing the metadata? that seems wrong/strange.)

Not sure if we want to do it always, or only when it is free to invert?


Repository:
  rL LLVM

https://reviews.llvm.org/D50301

Files:
  lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  test/Transforms/InstCombine/and-or-not.ll
  test/Transforms/InstCombine/demorgan-sink-not-into-xor.ll
  test/Transforms/InstCombine/or-xor.ll
  test/Transforms/InstCombine/set.ll

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