RFR: 8302908: RISC-V: Support masked vector arithmetic instructions for Vector API [v14]

[Dingli Zhang]

On Tue, 11 Apr 2023 02:51:35 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Dingli Zhang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove unneeded combination nodes
>
> src/hotspot/cpu/riscv/riscv_v.ad line 2562:
> 
>> 2560: 
>> 2561: instruct vmaskcast_same_esize_rvv(vRegMask dst_src) %{
>> 2562:   predicate(Matcher::vector_length_in_bytes(n) == Matcher::vector_length_in_bytes(n->in(1)));
> 
> Can we add support for other cases for VectorMaskCast at the same time?

Each bit in the mask register in RVV always corresponds to an element, and there is no need to convert the width of the mask according to the type of vector element, as in aarch64.

So we just need to remove the predicate here and change the instruct name to make it match the logic, which is the same as x86 AVX512[1].

[1] https://github.com/openjdk/jdk/blob/cd7d53c88c27eedbe16020b88c2219708d170a1e/src/hotspot/cpu/x86/x86.ad#L8326-L8334

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PR Review Comment: https://git.openjdk.org/jdk/pull/12682#discussion_r1162481559