RFR: 8328181: C2: assert(MaxVectorSize >= 32) failed: vector length should be >= 32 [v2]

[Emanuel Peter]

On Mon, 8 Apr 2024 02:35:33 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> This bug fix patch tightens the predication check for small constant length clear array pattern and relaxes associated feature checks. Modified few comments for clarity.
>> 
>> Kindly review and approve.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Cleanup predicates.

src/hotspot/cpu/x86/x86.ad line 1753:

> 1751:       }
> 1752:       break;
> 1753:     case Op_ClearArray:

This seems problematic, and may lead to the regression in https://bugs.openjdk.org/browse/JDK-8332487

On non-AVX512 platforms, this is now always `true` instead of always `false`. Probably this was not intended, and you thought this way going to be default `false`?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18464#discussion_r1616735713