RFR: 8318217: RISC-V: C2 VectorizedHashCode [v10]

[Fei Yang]

On Fri, 8 Dec 2023 08:29:00 GMT, Yuri Gaevsky <duke at openjdk.org> wrote:

>> src/hotspot/cpu/riscv/c2_MacroAssembler_riscv.cpp line 1541:
>> 
>>> 1539: 
>>> 1540:   bind(TAIL);
>>> 1541:   beqz(cnt, DONE);
>> 
>> `cnt` is non-zero we reach here from L1498, so this `beqz` check seems redundant in that case. Maybe move this `beqz` check immediate after L1538?
>
> We need this check because after wide "unrolling" loop the cnt could be 0,1,2 or 3, see "don't forget about tail" comment at the line 1502.

The control flow will be directed to `DONE` by the `beqz` check at L1493 when `cnt` is zero.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16629#discussion_r1420461406