RFR: 8324751: C2 SuperWord: Aliasing Analysis runtime check [v11]

[Emanuel Peter]

On Sun, 17 Aug 2025 21:09:58 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   more documentation for Christian
>
> src/hotspot/share/opto/loopUnswitch.cpp line 569:
> 
>> 567:   // optimizations. That means the slow_loop should still be correct, but
>> 568:   // a bit slower, as there is no unrolling etc.
>> 569:   if (!LoopMultiversioningOptimizeSlowLoop) {
> 
> Do we really need this in product?  Your benchmarks results shows that we need to optimize slow loop. I can bet nobody will use this flag in real word.

It is a DIAGNOSTIC flag, which allowed me to demonstrate the performance in a JMH benchmark. You asked for that benchmark back when I first introduced multiversioning with https://github.com/openjdk/jdk/pull/22016 . I'm also fine removing the flag completely now. Or just making it develop. What do you think is best?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24278#discussion_r2281385887