RFR: 8366490: C2 SuperWord: wrong result because CastP2X is missing ctrl and floats over SafePoint creating stale oops [v3]

[Emanuel Peter]

On Tue, 2 Sep 2025 12:54:23 GMT, Manuel Hässig <mhaessig at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Apply suggestions from code review
>>   
>>   Co-authored-by: Manuel Hässig <manuel at haessig.org>
>>   Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>
> test/hotspot/jtreg/compiler/loopopts/superword/TestAliasingCastP2XCtrl.java line 71:
> 
>> 69:             int[] a = new int[N];
>> 70:         }
>> 71:         // Makes GC more likely.
> 
> No clue if this is the right use case, but maybe this would be a good use of `-XX:+GCALot`?

Maybe, you could be right!

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PR Review Comment: https://git.openjdk.org/jdk/pull/27045#discussion_r2316033051