RFR: 8303762: Optimize vector slice operation with constant index using VPALIGNR instruction [v13]

[Jatin Bhateja]

On Tue, 17 Feb 2026 11:31:03 GMT, Quan Anh Mai <qamai at openjdk.org> wrote:

>> I think there is no harm in-lining fallback after first un-successful attempt of intrinsification for sliceOp, as fallback is composed of vectorAPI and we are giving them opportunity for intrinsificaiton, this save costly boxing operation and performance will be at par with what we have today.  WDYT ?
>
> But this will affect other intrinsics, too, they are not implemented using other vector API operations.

We only perform fallback inlining on first intrinsification failure for sliceOp, this is a very localized change.
https://github.com/jatin-bhateja/jdk/blob/1dfff5589c8b6c83dfc9810bddbb676c7982c904/src/hotspot/share/opto/callGenerator.cpp#L455

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PR Review Comment: https://git.openjdk.org/jdk/pull/24104#discussion_r2816730250