[lworld] RFR: 8354981: [lworld] Atomic flat stores need preceding CPUMemBar [v2]

[duke]

On Tue, 22 Apr 2025 17:17:38 GMT, Quan Anh Mai <qamai at openjdk.org> wrote:

>> Hi,
>> 
>> Atomic flat stores cover many memory slices. As a result, it needs a preceding CPUMemBar or else it only takes the slice of the first field as its memory input, which is incorrect.
>> 
>> I don't know how to make a regression test for this. I encounter this crash while working on JDK-8335256. The crash was due to the memory input of the flat store gets split during escape analysis. The compiler then tries looking at the flat stores, which is vastly different from what it expects.
>> 
>> Please take a look and leave your reviews, thanks a lot.
>
> Quan Anh Mai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:
> 
>  - Merge branch 'lworld' into fixatomicstore
>  - Atomic flat store needs a preceding barrier

@merykitty 
Your change (at version 890ca95177e6d8ef0dc0f1e783483f88b3b77441) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/valhalla/pull/1437#issuecomment-2824258797