[PATCH] D62342: [SelectionDAG] Enhance the simplification of `copyto` from `implicit-def`.

Mon May 27 06:52:48 PDT 2019

nhaehnle accepted this revision.
nhaehnle added a comment.
This revision is now accepted and ready to land.

In D62342#1515727 <https://reviews.llvm.org/D62342#1515727>, @arsenm wrote:

> In D62342#1515284 <https://reviews.llvm.org/D62342#1515284>, @nhaehnle wrote:
>
> > I don't think this is correct. If an IMPLICIT_DEF has multiple uses, then the correctness of the program may depend on all uses seeing the same value, even if that value is undefined.
>
>
> I don't think this is a guaranteed property. This is the MIR equivalent of the poison/freeze question, but today implicit_def doesn't give you this

Hmm alright. Then the change itself seems okay.

Repository:
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  https://reviews.llvm.org/D62342/new/

https://reviews.llvm.org/D62342