[PATCH] D111066: Disable "[SCEV] Prove implications of different type via truncation"

Mon Oct 4 10:41:49 PDT 2021

bjope planned changes to this revision.
bjope added a comment.

In D111066#3040370 <https://reviews.llvm.org/D111066#3040370>, @bjope wrote:

> In D111066#3040144 <https://reviews.llvm.org/D111066#3040144>, @nikic wrote:
>
>> Can the test case be reduced? I don't think we want to add a 5000 line test case for this.
>
> I made some attempts using bugpoint earlier (and this is actually a bit reduced compared to the original test case). A bit tricky to set it up as the fail scenario is that there should be a timeout, and then it will take lots of time to get bugpoint to actually reduce anything.
> I also made some attempts adding some kind of debug printouts to detect failure by identifying some repeated patterns when calling ScalarEvolution::isImpliedCond, but never managed to get that working properly.
> If I knew what the problem is it might be easier to reduce it ;-)
>
> If anyone got some ideas on how to tackle the problem with reducing it I wouldn't mind testing those ideas.
>
> (Maybe I should give "bugpoint + timeout" another try. But I think I need quite a long timeout setting, so it takes some time if it only attempts to remove 1 instruction every 5 minutes or so.)

Was a couple of weeks ago that I tried reducing this the last time. Now I've at least managed to reduce it a bit more manually (removing some stores/calls/branches, and then running with -dce -simplifycfg, etc). I'll continue a bit more and then I'll update this patch.

Repository:
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https://reviews.llvm.org/D111066