RFR: 8354348: Enable Extended EVEX to REX2/REX demotion for commutative operations with same dst and src2 [v2]

[Srinivas Vamsi Parasa]

On Tue, 2 Sep 2025 02:40:59 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Srinivas Vamsi Parasa has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
>> 
>>  - nomenclature change
>>  - Merge branch 'master' of https://git.openjdk.java.net/jdk into cdemotion
>>  - remove trailing whitespaces
>>  - remove unused instructions
>>  - 8354348: Enable Extended EVEX to REX2/REX demotion for commutative operations with same dst and src2
>
> src/hotspot/cpu/x86/x86_64.ad line 7121:
> 
>> 7119: %{
>> 7120:   predicate(UseAPX);
>> 7121:   match(Set dst (AddI (LoadI src1) src2));
> 
> Will this not be covered by the pattern at line 7103, since ADLC automatically generates a DFA to handle both cases?

Will run experiments to make sure that the RegRegMem pattern also applies to RegMemReg case and remove the newly added match rules if they're redundant. Will update you soon.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26997#discussion_r2323424398