RFR: 8282875: AArch64: [vectorapi] Optimize Vector.reduceLane for SVE 64/128 vector size

[Ningsheng Jian]

On Mon, 28 Mar 2022 17:36:48 GMT, Andrew Haley <aph at openjdk.org> wrote:

> Out of curiosity, how do we propose to distinguish when we should use SVE? I guess as long as we only have Neoverse V1/N2 for SVE it makes sense to concentrate on that, but I guess we'll want a better optimization model sooner or later.

Indeed, that's what we need to resolve. Currently, we don't have a good model yet, so we just trying not to use SVE if it doesn't win. We are also trying to merge current neon/sve ad files into single one. Hopefully that will make codegen easier to choose SVE/NEON, e.g. for small vector lengths.

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PR: https://git.openjdk.java.net/jdk/pull/7999