[PATCH] D112300: [InstCombine] Don't split up Loads and free Exts

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D112300#3084234 <https://reviews.llvm.org/D112300#3084234>, @spatel wrote:

> In D112300#3084164 <https://reviews.llvm.org/D112300#3084164>, @avieira wrote:
>
>> @spatel Yeah that's where I first made the change, but as I was working on it I noticed the original transformation was being done in InstCombine and as a practice I prefer to prevent transformations rather than undo them. I am guessing we are not in agreement on that. I've started reworking the original approach to do it in TypePromotion.
>
> I actually agree that code sinking shouldn't be in instcombine, or it should be limited in some way (and there is a debug flag to disable it).

Check: by sinking, are you talking about just moving instructions into other blocks closer to their users?
Because the change here is not about that, but about [not] folding phi-of-loads to load-of-phi, i believe.

> But making that change is probably a difficult series of patching other passes and/or the opt pipeline to deal with regressions. If someone wants to take that on, I'd support the effort.




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https://reviews.llvm.org/D112300