[PATCH] D89548: [SCEV] Prove implications of different type via truncation

Mon Oct 4 09:05:15 PDT 2021

bjope added a comment.

In D89548#3026933 <https://reviews.llvm.org/D89548#3026933>, @bjope wrote:

> In D89548#3009262 <https://reviews.llvm.org/D89548#3009262>, @uabelho wrote:
>
>> Hi @mkazantsev ,
>>
>> The following hang started occuring with this patch:
>>  https://bugs.llvm.org/show_bug.cgi?id=51869
>>
>> I've also seen hangs in loop-idiom-recognizer with the patch so I suppose many passes using SCEV might run into the same kind of problems.
>
> I haven't tried to revert this patch, but maybe that should be explored (as it seems broken in the sense that it might cause infinite looping / severe compile time regressions)?

Not a pure revert, but here is a patch to disable this feature by default: https://reviews.llvm.org/D111066

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D89548