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

[Hamlin Li]

On Tue, 11 Nov 2025 11:24:12 GMT, Hamlin Li <mli at openjdk.org> wrote:

> 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

@eme64 Could you have a look? :)

Not sure who else can help to review it, feel free to help have a look if you're available. :)

Thanks!

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PR Comment: https://git.openjdk.org/jdk/pull/28231#issuecomment-3516425353