RFR: 8355980: RISC-V: remove vmclr_m before vmsXX and vmfXX

[Fei Yang]

On Wed, 30 Apr 2025 14:46:23 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Hi,
> Can you help to review this simple improvement?
> 
> By rvv spec,
> "integer compare instructions write 1 to the destination mask register element if the comparison evaluates to true, and 0 otherwise."
> "These vector FP compare instructions compare two source operands and write the comparison result to a mask register. "
> 
> So, it's not always necessary to clear the mask register before vector comparison operation, e.g. when `vm != Assembler::v0_t`.
> 
> Thanks!

Thanks!

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Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24968#pullrequestreview-2808915411