[jdk17u-dev] RFR: 8350483: AArch64: turn on signum intrinsics by default on Ampere CPUs

[Patrick Zhang]

On Mon, 3 Mar 2025 09:18:32 GMT, Goetz Lindenmaier <goetz at openjdk.org> wrote:

> Hi @cnqpzhang , can you please backport to 24 and 21 first? Removing the label in the meantime. Performance optimizations are not necessarily good candidates for backport to a rather old release.

Thanks for your comments, @GoeLin .
Sure I will request for backports to 24 and 21 firstly. 
It is not just a performance optimization, in the worst cases the slowdown caused by the performance issue showed `80~100x` time cost of normal cases, as such the functions at `1~2%` of the expected run speed got severely impacted in a manner.

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PR Comment: https://git.openjdk.org/jdk17u-dev/pull/3300#issuecomment-2696017536