RFR: 8353686: Optimize Math.cbrt for x86 64 bit platforms [v6]

[Mohamed Issa]

On Mon, 2 Jun 2025 02:08:55 GMT, David Holmes <dholmes at openjdk.org> wrote:

> This change also broke most of the non-x86 platforms, due to the new intrinsic not being implemented on those platforms.

When you say "most of the non-x86 platforms", are you referring to the ones with processor types listed below?

1. jdk/src/hotspot/cpu/**arm**
2. jdk/src/hotspot/cpu/**ppc**
3. jdk/src/hotspot/cpu/**s390**

I don't see a cbrt intrinsic implementation in the non-x86 platforms. However, the ones listed above appear to get to the _ShouldNotReachHere_ error state if a particular intrinsic isn't found in `TemplateInterpreterGenerator::generate_math_entry` (`templateInterpreterGenerator_*.cpp`). It looks like aarch64 and riscv don't take that route and would fall back to the default cbrt implementation.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/24470#issuecomment-2928618217