[PATCH] D43876: [LoopUnroll] Peel off iterations if it makes conditions true/false.

[Chad Rosier via Phabricator via llvm-commits]

mcrosier added a comment.

In https://reviews.llvm.org/D43876#1057247, @mcrosier wrote:

> In https://reviews.llvm.org/D43876#1050460, @fhahn wrote:
>
> > @mcrosier I've submitted https://reviews.llvm.org/D44983 for review. It prevents peeling, if we cannot simplify the loop body after peeling. Peeling if we cannot simplify the loop body afterwards is likely not beneficial. It would be great if you could check if that helps in your case. If it's not easy for you to check, I can try and test it myself.
> >
> > Coming up with some additional heuristics, e.g. based on the number of instructions peeled and not eliminated, should be possible, but without knowing the inlining situation we would probably have to choose a rather arbitrary threshold.
>
>
> Sure, I'll take a look now and let you know!  Sorry I didn't see this sooner.


Unfortunately, https://reviews.llvm.org/D44983 does not fix this case. I'm going to dig into this now.  I'll update you once I have some additional findings.


Repository:
  rL LLVM

https://reviews.llvm.org/D43876