RFR: 8331577: RISC-V: C2 CountLeadingZerosV [v3]

[Hamlin Li]

> 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 ReverseBytesV & PopCountV by sharing dst&src regs

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19153/files
  - new: https://git.openjdk.org/jdk/pull/19153/files/1d5d17fe..0aaa0834

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19153&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19153&range=01-02

  Stats: 9 lines in 1 file changed: 0 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/19153.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19153/head:pull/19153

PR: https://git.openjdk.org/jdk/pull/19153