RFR: 8359965: Enable paired pushp and popp instruction usage for APX enabled CPUs [v2]

[Srinivas Vamsi Parasa]

On Mon, 14 Jul 2025 08:15:13 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Srinivas Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   rename to paired_push and paired_pop
>
> src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp line 114:
> 
>> 112:         __ paired_push(rax);
>> 113:       }
>> 114:       __ paired_push(rcx);
> 
> Hi @vamsi-parasa , for consecutive push/pop we can use push2/pop2 and 16byte alignment can be  guaranteed using following technique 
> https://github.com/openjdk/jdk/pull/25351/files#diff-d5d721ebf93346ba66e81257e4f6c5e6268d59774313c61e97353c0dfbf686a5R94

Hi Jatin (@jatin-bhateja), for the first iteration, would it be ok to get the push_paired/pop_paired changes integrated and then make the push2p/pop2p related optimizations in a separate PR?

Thanks,
Vamsi

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PR Review Comment: https://git.openjdk.org/jdk/pull/25889#discussion_r2205447287