RFR: 8332153: RISC-V: enable tests and add comment for vector shift instruct (shared by vectorization and Vector API)

[Ludovic Henry]

On Thu, 16 May 2024 11:12:09 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Hi,
> Can you help to review this patch?
> For vector shift instruct, some corresponding tests are not enabled, this is to enable them.
> And the way how vector shift instruct works is not clear, especially both vectorization (SLP in jdk) and Vector API share the same instruct's in riscv_v.ad, so also added some comment to clarify it.
> 
> Thanks

src/hotspot/cpu/riscv/riscv_v.ad line 1802:

> 1800: // and https://github.com/riscv/riscv-v-spec/blob/master/v-spec.adoc#116-vector-single-width-shift-instructions for details.
> 1801: //
> 1802: // Although the difference between these 2 behaviours, the same shift instruct's of byte and short are

Suggestion:

// Despite the difference between these 2 behaviours, the same shift instruct's of byte and short are

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PR Review Comment: https://git.openjdk.org/jdk/pull/19265#discussion_r1603196839