[PATCH] D37195: [InstCombine] Teach canEvaluateTruncated and EvaluateInDifferentType to handle expression tree with multi-used nodes.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D37195#855385, @aaboud wrote:

> I do not see why it is much different that passing the demandedBits map and update it recursively!


That may be true, but there's also an argument that doing demandedBits analysis within instcombine already went over the line. :)
There have been a few recent llvm-dev threads about the responsibilities and limits of various passes. Here's one: 
http://lists.llvm.org/pipermail/llvm-dev/2017-May/113212.html

I don't have enough experience with this, so I'll defer to others for their guidance. Just thought it was worth mentioning.


https://reviews.llvm.org/D37195