RFR: 8357554: Enable vectorization of Bool -> CMove with different type size (on riscv) [v3]

[Hamlin Li]

> Hi,
> 
> Can you help to review this patch?
> 
> This patch enables the vectorization of statement like `op_1 bop op_2 ? res_f_d_1 : res_f_d_2` in a loop, where op_x's size is different from res_f_d_x's.
> 
> To assist with code review, this pr contains only the shared code change, is splitted from https://github.com/openjdk/jdk/pull/28230, which enable & implement the riscv part. The similar optimization could be extended to other platforms. 
> 
> ## Some background
> 
> Previously, it's https://github.com/openjdk/jdk/pull/25336, which was blocked by unsigned comparison issue. The issue was recently resolved by https://github.com/openjdk/jdk/pull/27942, so I'm re-start working on this optimization.
> 
> This pr only relaxes one of the constraints in https://github.com/openjdk/jdk/pull/25336, i.e. transform CMoveF/D to vector operations no matter what's the size of comparison's operator, but remove the optimization of transform CMoveI/L to vector operations which I think need more investigation.
> 
> # Test
> ## Jtreg
> 
> in progress...
> 
> ## Performance
> 
> check the performance data in https://github.com/openjdk/jdk/pull/25341 on riscv.
> 
> Thanks

Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:

  fix typo

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/28231/files
  - new: https://git.openjdk.org/jdk/pull/28231/files/cfbe0a65..a89d26c4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28231&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28231&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28231.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28231/head:pull/28231

PR: https://git.openjdk.org/jdk/pull/28231