[PATCH] D99205: Add jump-threading optimization for deterministic finite automata

[Ehsan Amiri via Phabricator via llvm-commits]

amehsan added a comment.

In D99205#2923056 <https://reviews.llvm.org/D99205#2923056>, @SjoerdMeijer wrote:

> Just a heads up. I have benchmarked this version against our downstream implementation of jump threading and see some regressions:
>
>          Regression
>   core1  0.4%
>   core2  0.28%
>   core3  2.7%
>   core4  0.24%
>   core5  1.12%
>
> Especially for the more capable cores "core3" and "core5" the difference is quite big, so we do leave some performance on the table.
>
> I will probably add a reproducer as a regression test and raise a ticket for this, so that we can look into this.

Thanks Sjoerd for the careful review of this patch and feedback provided. It will be interesting to see if the root cause of the performance degradation is in the code generated by the pass, or not. If that is the case, we can investigate whether changing the code gen in this pass is the best way forward, or some extra clean up/optimization is needed somewhere else. We will look into it when more information is available. Thanks again for all the feedback.


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