RFR: 8331577: RISC-V: C2 CountLeadingZerosV [v2]

[Hamlin Li]

On Thu, 9 May 2024 09:48:09 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you help to review this patch adding CountLeadingZerosV and CountTrailingZerosV instrinsics?
>> Thanks.
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix masked issue

NOTE: the reason why let dst and src share one register (i.e. `(vReg dst_src, vRegMask_V0 v0)`) in masked version is that for inactive elements, we should keep the origin value, neither `mu` or `ma` will do it.

BTW, I will also re-visit all existing masked version instructions to make sure it works as expected.

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PR Comment: https://git.openjdk.org/jdk/pull/19153#issuecomment-2102392793