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

[Jatin Bhateja]

On Tue, 28 May 2024 09:47:08 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> 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`?
>
> I don't understand what you are implying. Are you saying this is not the reason for the regression?

Yes, this can cause regression since now on non-AVX512 targets compiler may not emit StoreL based instruction sequence and select one of the clear array pattern based on target feature checks.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/18464#discussion_r1616958675