RFR: 8361353: [PPC64] C2: Add nodes UMulHiL, CmpUL3, UMinV, UMaxV, NegVI [v6]

[David Briemann]

On Tue, 8 Jul 2025 11:51:36 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

>> Because we have made the experience that the vector instructions for longs are very slow on PPC. So far all of them I tried or implemented were slower than the non-vectorized alternative.
>
> Ok I remember that. Why have you implemented `VMINU` and `VMAXU` for `T_LONG` then?

I tried several nodes/instructions also for longs but most of them performed worse and I removed them.
`VMINU` and `VMAXU` did at least perform the same or slightly better than the non-vectorized variant. So @TheRealMDoerr and I decided to keep them.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26115#discussion_r2192314419