RFR: 8300148: Consider using a StoreStore barrier instead of Release barrier on ctor exit [v7]

[Joshua Cao]

On Wed, 3 Apr 2024 08:44:07 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Joshua Cao has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Statistics for barriers generated/eliminated
>>  - global flag to turn on storestore barrier emission and membar acquires
>>    IR tests
>
> src/hotspot/share/opto/memnode.cpp line 3438:
> 
>> 3436:         }
>> 3437:       }
>> 3438:     } else if (opc == Op_MemBarRelease || opc == Op_MemBarStoreStore) {
> 
> Should be protected by a feature flag?

I don't think the feature flag is needed for these cases. These are optimizations to support the changes in code shape introduced by the feature, not the feature itself. If the feature flag is off, there should be no change in behavior.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/18505#discussion_r1550322871