[PATCH] D65148: [SimplifyCFG] Bump phi-node-folding-threshold from 2 to 3

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D65148#1607019 <https://reviews.llvm.org/D65148#1607019>, @lebedev.ri wrote:

> In D65148#1606899 <https://reviews.llvm.org/D65148#1606899>, @lebedev.ri wrote:
>
> > In D65148#1603922 <https://reviews.llvm.org/D65148#1603922>, @dmgreen wrote:
> >
> > > ...
> >
> >
> > Hmm, i never got this mail, sorry for not noticing this reply. Thank you for looking into it!
> >  I believe this shows the change: https://godbolt.org/z/Mb6T3R
> >  That indeed looks not great. But i think i'm missing something.
> >  That replacement does not look correct to me: https://rise4fun.com/Alive/CNns
> >  Did you run the tests, too, or only benchmarks?
>
>
> Ok so roughly, the generalization seems to be: https://rise4fun.com/Alive/6Ey
>
> I *think* that will handle the case you hit - https://godbolt.org/z/n35hPH
>  The weird constant is because it get's shrunk since those bits are not being used.
>  I think that happens late[r] in pipeline..
>
> We indeed currently don't catch it: https://godbolt.org/z/14si0q
>  We could: https://rise4fun.com/Alive/ZeC


And some procastination later, D65765 <https://reviews.llvm.org/D65765>, PTAL.


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https://reviews.llvm.org/D65148