RFR: 8293531: C2: some vectorapi tests fail assert "Not monotonic" with flag -XX:TypeProfileLevel=222

[Vladimir Kozlov]

On Tue, 11 Oct 2022 20:40:19 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Problem occurs in iterative DF analysis during CCP optimization, meet operations drops the speculative types before converging participating lattice values since [include_speculative argument it receives is always set to false ](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/type.hpp#L231)where as [equality check ](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/phaseX.cpp#L1751) in the failing assertion is performed against original type still carrying the speculative type.
>> 
>> To fix this, type comparison in the assertion should also be done after stripping the speculative type, with this change intermittent assertion failures in several vector API tests reported in the bug report  are no longer seen.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Could this bug explain JDK-8295028?

> Hi @dean-long, @vnkozlov , please let me know if this can be checked in.

Yes, you can push.

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PR: https://git.openjdk.org/jdk/pull/10648