[PATCH] D36988: [InstCombine] fix and enhance udiv/urem narrowing

[Sanjay Patel via Phabricator via llvm-commits]

spatel created this revision.
Herald added a subscriber: mcrosier.

There are 3 independent changes here, but I thought it would be easier to review one patch to handle them all. If it's better to review and/or commit separately, please let me know:

1. Account for multiple uses in the pattern matching: avoid the transform if it increases the instruction count.
2. Add a missing fold for the case where the numerator is the constant: http://rise4fun.com/Alive/E2p
3. Enable all folds for vector types.

There's still one more potential change - use "shouldChangeType()" to keep from transforming to an illegal integer type.


https://reviews.llvm.org/D36988

Files:
  lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
  test/Transforms/InstCombine/udivrem-change-width.ll

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