RFR: 8310691: [REDO] [vectorapi] Refactor VectorShuffle implementation [v2]

[Quan Anh Mai]

On Thu, 5 Dec 2024 20:48:07 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

>> `shuffleFromOp` is a slow path op so I don't think it is. Additionally, our vector multiplication is against a scalar, too. So we can optimize it if `step` is a constant.
>
> I incorrectly read `!=` as `==` :-) as that is the more common pattern used in the code base, so i was thinking the power of two code path was using `shuffleFromOp`. Could you invert the check to be more consistent?

This piece of code follows the pattern:

    if (uncommonCondition) {
        return uncommonPath();
    }
    // Continue the common path

So I think it is better to keep it as it is.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21042#discussion_r1872901230