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

[Srinivas Vamsi Parasa]

On Mon, 1 Sep 2025 13:17:23 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/assembler_x86.cpp line 13055:
> 
>> 13053:   bool is_prefixq = (size == EVEX_64bit) ? true : false;
>> 13054:   bool normal_demotion = is_demotable(no_flags, dst_enc, nds_enc);
>> 13055:   bool commutative_demotion = is_commutative && is_demotable(no_flags, dst_enc, src_enc);
> 
> Nomenclature change: instead of normal_demotion and commutative demotion, it will be more appropriate to use first/second_operand_demotable.

Please see the updated nomenclature changed in the updated code as suggested.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26997#discussion_r2323411449