RFR: 8304450: [vectorapi] Refactor VectorShuffle implementation [v6]

Mon Apr 10 18:43:25 UTC 2023

On Mon, 10 Apr 2023 15:11:55 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Thanks a lot for your review, I think that transforming a multiplication by a power of 2 into a shift can be done by the C2 compiler. I have added the special case for `start = 0 && step == 1` since it may be more common and can be optimised away when the arguments are constants.
>
> For x86 byte vector multiplication is done at granularity of short lanes, this case shows regression with power of two multiplications which are strength reduced to shifts currently. please file a follow up bug report for this.

@jatin-bhateja I have created [JDK-8305810](https://bugs.openjdk.org/browse/JDK-8305810)

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PR Review Comment: https://git.openjdk.org/jdk/pull/13093#discussion_r1161976583