RFR: 8322174: RISC-V: C2 VectorizedHashCode RVV Version [v10]

[Fei Yang]

On Tue, 15 Jul 2025 14:05:25 GMT, Yuri Gaevsky <duke at openjdk.org> wrote:

>> The patch adds possibility to use RVV instructions for faster vectorizedHashCode calculations on RVV v1.0.0 capable hardware.
>> 
>> Testing: hotspot/jtreg/compiler/ under QEMU-8.1 with RVV v1.0.0.
>
> Yuri Gaevsky has updated the pull request incrementally with one additional commit since the last revision:
> 
>   - removed tail processing with RVV instructions as simple scalar loop provides in general better results

Looking at the JMH numbers, it's interesting to find that `-XX:DisableIntrinsic=_vectorizedHashCode` outperforms `-XX:-UseRVV`.
If that is the case, then why would we want the scalar version (that is `C2_MacroAssembler::arrays_hashcode()`)?

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PR Comment: https://git.openjdk.org/jdk/pull/17413#issuecomment-3082664335