Integrated: 8353686: Optimize Math.cbrt for x86 64 bit platforms

[Mohamed Issa]

On Sun, 6 Apr 2025 03:48:22 GMT, Mohamed Issa <duke at openjdk.org> wrote:

> The goal of this PR is to implement an x86_64 intrinsic for java.lang.Math.cbrt() using libm. There is a new set of micro-benchmarks are included to check the performance of specific input value ranges to help prevent regressions in the future.
> 
> The command to run all range specific micro-benchmarks is posted below.
> 
> `make test TEST="micro:CbrtPerf.CbrtPerfRanges"`
> 
> The results of all tests posted below were captured with an [Intel® Xeon 6761P](https://www.intel.com/content/www/us/en/products/sku/241842/intel-xeon-6761p-processor-336m-cache-2-50-ghz/specifications.html) using [OpenJDK v25-b21](https://github.com/openjdk/jdk/releases/tag/jdk-25%2B21) as the baseline version.
> 
> For performance data collected with the new built in range micro-benchmark, see the table below. Each result is the mean of 8 individual runs, and the input ranges used match those from the original Java implementation. Overall, the intrinsic provides a major uplift of 169% when very small inputs are used and a more modest uplift of 45% for all other inputs.
> 
> | Input range(s)                                  | Baseline throughput (ops/ms) | Intrinsic throughput (ops/ms) | Speedup |
> | :-------------------------------------: | :-------------------------------: | :-------------------------------: | :---------: |
> | [-2^(-1022), 2^(-1022)]                   | 6568                                        | 17678                                      | 2.69x       |
> | (-INF, -2^(-1022)], [2^(-1022), INF) | 138932                                    | 200897                                    | 1.45x       |
> 
> Finally, the `jtreg:test/jdk/java/lang/Math/CubeRootTests.java` test passed with the changes.

This pull request has now been integrated.

Changeset: 0df8c968
Author:    Mohamed Issa <mohamed.issa at intel.com>
Committer: Sandhya Viswanathan <sviswanathan at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/0df8c9684b8782ef830e2bd425217864c3f51784
Stats:     649 lines in 27 files changed: 637 ins; 1 del; 11 mod

8353686: Optimize Math.cbrt for x86 64 bit platforms

Reviewed-by: sviswanathan, sparasa, jbhateja

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PR: https://git.openjdk.org/jdk/pull/24470