RFR: 8262355: Support for AVX-512 opmask register allocation. [v8]

[Ningsheng Jian]

On Tue, 16 Mar 2021 12:53:42 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8262355: Removing object re-materialization handling for mask-generating nodes during de-opt, it will be added separately.
>
> src/hotspot/share/opto/type.cpp line 664:
> 
>> 662:   _zero_type[T_CONFLICT]= NULL;
>> 663: 
>> 664: #if defined(X86)
> 
> Why is it `X86`-specific? Should it be simply guarded by `Matcher::has_predicated_vectors()` instead?

Yes, SVE should also be fine with this. Perhaps to use the default type TypeInt::BYTE instead of TypeInt::BOOL? It seems that masking byte type looks more reasonable?

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PR: https://git.openjdk.java.net/jdk/pull/2768