RFR: 8374043: C2: assert(_base >= VectorMask && _base <= VectorZ) failed: Not a Vector

[Xiaohong Gong]

On Thu, 8 Jan 2026 08:16:04 GMT, Manuel Hässig <mhaessig at openjdk.org> wrote:

> A drive-by comment on the reproducibility:
> 
> * Does this only reproduce for specific hardware features or on all relatively new vector instruction sets?

Thanks for looking at this PR! This can be reproduced on hardwares that 1) support vector api well in backend, 2) do not support predicate features like AVX-512 and RVV.

> * Have you tried to reproduce this using the `StressSeed` flag? In the hs-error file you should find it with all the hotspot flags and rerunning the test with that seed often leads to a reproducible failure.

Yes, I can reproduce this issue with all the stress flags reported in the hs-error file, but limited to the existing test case and the failure still happens randomly. I tried with the failure seed, but I failed to reproduce with it.

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PR Comment: https://git.openjdk.org/jdk/pull/29057#issuecomment-3722785955