[PATCH] D36486: [InstCombine] Don't fall back to only calling computeKnownBits if the upper bit of Add/Sub is demanded.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

Is there a potential function difference here, or is this just an efficiency improvement from calling KnownBits::computeForAddSub() directly?


https://reviews.llvm.org/D36486