[PATCH] D93317: [LV] Vectorize (some) early and multiple exit loops

Thu Dec 24 09:15:28 PST 2020

fhahn added a comment.

> In D93317#2470271 <https://reviews.llvm.org/D93317#2470271>, @fhahn wrote:
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>> 
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> I can confirm the failure and will debug.  Thank you again for finding a cornercase.
>
> Florian, do you mind if I landed this under an off by default flag?  I realize we have correctness issues outstanding, but it would be a lot easier to test this, and highlight the fixes one by one if I was working off checked in code.  Once we'd worked through everything, I'd enable and remove the flag.

IMO it would be preferable to land this without a flag, so we ensure this gets wide testing and we can flush out & fix the remaining issues early. I think it is almost there. I'll look into the issue over the next few days and I suggest to circle back after the holiday weekend and either land the patch together with a fix or behind a flag.

In D93317#2471303 <https://reviews.llvm.org/D93317#2471303>, @Ayal wrote:

> Hmm, if it is reduced a bit further by fusing bb9 into bb5, making the loop bottom-tested, same failure still occurs, regardless of this patch?

Thanks Ayal! I had a suspicion that this crash only got surfaced when using the patch, as the code related to setting up the `middle` block & co is not really touched by this patch. I'll try to take a look over the next few days.

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