RFR: 8283435: AArch64: [vectorapi] Optimize SVE lane/withLane operations for 64/128-bit vector sizes

Thu Apr 14 09:20:12 UTC 2022

On Wed, 13 Apr 2022 10:07:15 GMT, Joshua Zhu <jzhu at openjdk.org> wrote:

> This change looks good to me. I made a round of JMH test against lane/withLane operations.
> 
> Byte128Vector.withLane +12.90% Double128Vector.withLane +47.67% Float128Vector.withLane +11.57% Int128Vector.withLane +27.96% Long128Vector.withLane +50.06% Short128Vector.withLane +0.92% Byte128Vector.laneextract +51.61% Double128Vector.laneextract +17.27% Float128Vector.laneextract +12.13% Int128Vector.laneextract +32.50% Long128Vector.laneextract +38.12% Short128Vector.laneextract +48.66%
> 
> The above cases benefit from this optimization on my SVE hardware.

The data looks positive, though not as good as @theRealELiu's data. The patch looks good to me.

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PR: https://git.openjdk.java.net/jdk/pull/7943