RFR: 8373724: Assertion failure in TestSignumVector.java with UseAPX [v3]

[Sandhya Viswanathan]

On Fri, 2 Jan 2026 05:45:58 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Existing demotable instruction patterns for negI/L_rReg_ndd have 'src' as their second operand, this leads to an failure during register biasing. Changing the NDD demotion flags names to encode explicit operand position i.e. **Flag_ndd_demotable_opr1 and Flag_ndd_demotable_opr2** , splitting commutative flag into seperate new flags and fine tuning assertion checks based on new naming convention fixes the issue.
>> 
>> Failing test test/hotspot/jtreg/compiler/vectorization/TestSignumVector.java passes with the patch.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>> PS: Validation performed using Intel SDE 9.58.
>
> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
> 
>  - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8373724
>  - 8373724: Assertion failure in TestSignumVector.java with UseAPX

@jatin-bhateja Thanks for looking into this. There is a build failure in GHA with the following message:
"src/hotspot/cpu/x86/x86.ad:2645:13: error: ‘bool is_ndd_demotable(const MachNode*)’ defined but not used [-Werror=unused-function]"

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PR Comment: https://git.openjdk.org/jdk/pull/28999#issuecomment-3711301714