RFR: 8373724: Assertion failure in TestSignumVector.java with UseAPX [v6]

[Daniel Lundén]

On Wed, 7 Jan 2026 02:15:22 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 incrementally with one additional commit since the last revision:
> 
>   Review comments resolutions

I agree with these changes. Nice that the assert caught this case!

I'm running some tests for the changeset over the weekend, for both JDK 26 and JDK 27. I'll report back on Monday, and then you can go ahead with the backport @missa-prime (if no issues show up in testing).

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PR Comment: https://git.openjdk.org/jdk/pull/28999#issuecomment-3730438445