[PATCH] D30757: [LoopUnroll] Handle loops where the exiting block is different from the latch

Wed Mar 15 16:58:19 PDT 2017

mkuper added a comment.

In https://reviews.llvm.org/D30757#702345, @mzolotukhin wrote:

> Looks good to me, but, as you noticed in the PR - do we want to work with such loops at all? Did you check what happens if we just bail out on such loops?
>
> Michael

No, but I'm tempted to, because I think we have more bugs related to irreducible control flow that this patch doesn't fix.

Do you know if we already have a utility somewhere that detects this? There's no way to get this information out of LoopInfo that I'm aware of.
LV rolls its own ( hasCyclesInLoopBody() ), which would be fine for my original use case, but r296898 started handling non-innermost loops.

https://reviews.llvm.org/D30757