[jdk21u-dev] RFR: 8325277: [21u] compiler/c2/cr7200264/TestIntVect.java fails after JDK-8291809 with fastdebug build on aarch64 platform with SVE

[Paul Hohensee]

On Thu, 23 Oct 2025 03:01:26 GMT, SendaoYan <syan at openjdk.org> wrote:

> Hi all,
> 
> As discuss in [JDK-8325277](https://bugs.openjdk.org/browse/JDK-8325277), we want to backout the "backport JDK-8291809 to jdk21u-dev".
> 
> The test_divc and test_divc_n cannot be vectorized on 128-bit vector platforms with JDK 21u due to algorithmic constraints in superword.cpp, which led to the reported failure in [JDK-8325277](https://bugs.openjdk.org/browse/JDK-8325277).
> Starting from JDK 23, the algorithm has been significantly improved, and both cases can now be vectorized on 128-bit platforms, allowing the test to pass.
> 
> Test-fix only, risk is low.
> 
> Testing:
> 
> - [x] Run tests compiler/c2/cr7200264/TestSSE2IntVect.java compiler/c2/cr7200264/TestSSE4IntVect.java on linux-x64
> - [x] Run tests compiler/c2/cr7200264/TestSSE2IntVect.java compiler/c2/cr7200264/TestSSE4IntVect.java on linux-aarch64 without SVE2, jtreg shows no test.
> - [x] Run tests compiler/c2/cr7200264/TestSSE2IntVect.java compiler/c2/cr7200264/TestSSE4IntVect.java on linux-aarch64 with SVE2, jtreg shows no test.

Marked as reviewed by phh (Reviewer).

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PR Review: https://git.openjdk.org/jdk21u-dev/pull/2381#pullrequestreview-3385435806