RFR: 8359965: Enable paired pushp and popp instruction usage for APX enabled CPUs [v5]

[Jatin Bhateja]

On Thu, 17 Jul 2025 18:39:04 GMT, Srinivas Vamsi Parasa <sparasa at openjdk.org> wrote:

>> Srinivas Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   change to push_ppx/pop_ppx
>
> src/hotspot/cpu/x86/macroAssembler_x86.cpp line 806:
> 
>> 804: }
>> 805: 
>> 806: void MacroAssembler::pop_ppx(Register dst) {
> 
> Hi Jatin (@jatin-bhateja), the intent is to make the use of the `pushp/popp` instructions explicit to the user, as not all `push` or `pop` instructions require the PPX feature.

BTW, push/popp are meager optimization hints, if other constraints for balancing are not met the it will prevent value forwarding, so it's ok to keep the macro-assembly name same as the assembler name, fully qualified names Assembler::pop/push are sufficient to disambiguate in applicable scenarios or iff there is any such need.

I would have preferred keeping the same name to limit the changes in this patch.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25889#discussion_r2214135683