[PATCH] D129636: Fix a LSR debug invariance issue

Thu Aug 11 03:16:39 PDT 2022

chrisjackson added a comment.

In D129636#3715477 <https://reviews.llvm.org/D129636#3715477>, @markus wrote:

> In D129636#3715417 <https://reviews.llvm.org/D129636#3715417>, @mkazantsev wrote:
>
>> The best alternative I can suggest is to create a new ScalarEvolution instance and use it for dbg value queries. It should be good enough if the only purpose of that is to find undefs.
>
> That does sound like a very tempting alternative to be sure that these sort of issues do not crop up again. Not sure if it is possible though (@chrisjackson?)

I don't like the sound of duplicaring an entire ScalarEvolution, at first glance it seems expensive to me. I prefer a solution that avoids side-effects of obtaining the SCEV for a value.

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https://reviews.llvm.org/D129636