[PATCH] D48930: [InstCombine] Apply foldICmpUsingKnownBits to early bailout case

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D48930#1152683, @aditya_nandakumar wrote:

> In https://reviews.llvm.org/D48930#1152669, @mkazantsev wrote:
>
> > In https://reviews.llvm.org/D48930#1152458, @spatel wrote:
> >
> > > In https://reviews.llvm.org/D48930#1152437, @mkazantsev wrote:
> > >
> > > > The context is following: the patch https://reviews.llvm.org/rL336172 has broken this test, and I was asked to fix it.
> > >
> > >
> > > I assumed that much. :)
> > >  But are there any other examples that were given to you? The solution may depend on how varied the breakage is. If it's just this case, then we can probably get by with a solution that doesn't need value tracking.
> >
> >
> > It's the only example I have. @aditya_nandakumar, do you have any more tests where it matters?
>
>
> That was the simplest test case where I observed regression. There were quite a few more  - I didn't get a chance to look at them all.


I'd like to see more examples before trying to fix it. If it's just min/max cases that were broken, that can be a specific patch as I showed in the earlier comment, but if we regressed regular icmp patterns, then we might want to redo https://reviews.llvm.org/rL336172 by taking into account metadata rather than rearranging the folds.


https://reviews.llvm.org/D48930