RFR: 8329816: Add SLEEF version 3.6.1

[Hamlin Li]

On Thu, 29 Aug 2024 23:07:16 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> [JDK-8312425](https://bugs.openjdk.org/browse/JDK-8312425) is looking to optimize vector math operations by leveraging the SLEEF library. For legal reasons the actual contribution of the SLEEF files needs to be handled separately.
> 
> This is a new attempt at solving [JDK-8329816](https://bugs.openjdk.org/browse/JDK-8329816); the original attempt is here: https://github.com/openjdk/jdk/pull/19185. This PR is based on the discussions on how to move forward that was held in that original PR.

Thanks a lot for the quick response and effort!

I'm not qualified to review changes in make files, just have one general question below.

I also checked the git hash, and generated files, they're good.

Can I ask another general question in advance related to [subsequent pr](https://github.com/openjdk/jdk/pull/18605)? As there are several folders (`generated` and `upstream`) under src/jdk.incubator.vector/linux/native/libsleef/ now, what's the recommended way to only include `generated` and skip `upstream` when compile/build the final libsleef.so in that pr?

make/UpdateSleefSource.gmk line 105:

> 103: TARGETS := $(sleef_native_build)
> 104: 
> 105: $(eval $(call SetupExecute, sleef_cross_config, \

Not sure if it's still necessary or right to run the 2 steps build the second time, when native and cross-compilation are the same, e.g. build sve for aarch64 on an aarch64 machine.

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

PR Review: https://git.openjdk.org/jdk/pull/20781#pullrequestreview-2271712946
PR Review Comment: https://git.openjdk.org/jdk/pull/20781#discussion_r1738285588