RFR: 8341013: Optimize x86/aarch64 MD5 intrinsics by reducing data dependency [v2]

[Hamlin Li]

On Fri, 27 Sep 2024 11:43:06 GMT, Oli Gillespie <ogillespie at openjdk.org> wrote:

>> src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 3422:
>> 
>>> 3420:     reg_cache.extract_u32(rscratch1, k);
>>> 3421:     __ movw(rscratch2, t);
>>> 3422:     __ addw(rscratch4, r1, rscratch2);
>> 
>> Can you try to replace these 2 lines (3421-3422) with following?
>> 
>>     __ movw(rscratch4, t);
>>     __ addw(rscratch4, r1, rscratch4);
>> 
>> 
>> I expect it could bring more performance gain, but not sure.
>
> Thanks! I can't measure any difference at all with that change, seems to perform identically.

I see, Thanks!

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PR Review Comment: https://git.openjdk.org/jdk/pull/21203#discussion_r1778658786