RFR: 8358032: Use crypto pmull for CRC32(C) on Ampere CPU and improve for short inputs [v4]

[Emanuel Peter]

On Mon, 23 Jun 2025 05:48:48 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Liming Liu has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add the message for the assertions
>
> src/hotspot/cpu/aarch64/globals_aarch64.hpp line 92:
> 
>> 90:   product(bool, UseCryptoPmullForCRC32, false,                          \
>> 91:           "Use Crypto PMULL instructions for CRC32 computation")        \
>> 92:   product(uint, CryptoPmullForCRC32LowLimit, 256, DIAGNOSTIC,           \
> 
> Can you please add a test that uses this flag, and sets it to some selected values, and maybe even a random value?

Is there already an IR test that checks for the presence of the crypto pmull? That could be good to ensure it occurs as expected and only when expected :)

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PR Review Comment: https://git.openjdk.org/jdk/pull/25609#discussion_r2160771012