Integrated: 8367694: Fix jtreg test failure when Intel APX is enabled for KNL platforms

[Srinivas Vamsi Parasa]

On Mon, 15 Sep 2025 16:19:29 GMT, Srinivas Vamsi Parasa <sparasa at openjdk.org> wrote:

> This goal of this PR is fix the jtreg test failure observed in compiler test: `test/hotspot/jtreg/compiler/loopopts/superword/TestDependencyOffsets.java`
> 
> The test failure is occurring specifically for the tests with ids = {avx512-v064-A, avx512-v064-U, avx512-v032-A, avx512-v032-U}. These tests are run with KNL hardware features enabled (`-XX:+UseKNLSetting`). 
> 
> The two main causes of test failure are: 
> 1. KNL does not support Intel APX. Currently, APX is not turned off when using KNL. This PR fixes this issue.
> 2. BMI2 instructions like sarxl are encoded incorrectly with `uses_vl=true` (use vector length). This PR fixes the encoding to use the correct one:`uses_vl=false`.
> 
> After fixing these two bugs, `TestDependencyOffsets.java` is passing using the SDE emulator when APX is enabled.

This pull request has now been integrated.

Changeset: e883dec6
Author:    Srinivas Vamsi Parasa <sparasa at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/e883dec6be8cb2fc44e45a6b4677cca2f4df58ef
Stats:     34 lines in 2 files changed: 12 ins; 10 del; 12 mod

8367694: Fix jtreg test failure when Intel APX is enabled for KNL platforms

Reviewed-by: sviswanathan, epeter

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PR: https://git.openjdk.org/jdk/pull/27299