[PATCH] D75808: [ValueTracking] isKnownNonZero, computeKnownBits for freeze

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D75808#2260906 <https://reviews.llvm.org/D75808#2260906>, @aqjune wrote:

> In D75808#2260866 <https://reviews.llvm.org/D75808#2260866>, @fpichet wrote:
>
>> Another thing: I noticed that SelectionDAG::computeKnownBits doesn't deal with ISD::FREEZE.
>> Would it be ok to just call computeKnownBits (Op.getOperand(0)) to make it work. 
>> (Since Select_FREEZE just lower to a copy)
>
> It depends on whether SelDag has a poison value - does anyone know whether it has one?

We have nsw/nuw/exact flags on nodes, so that means poison exists?


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