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

[Ningsheng Jian]

On Tue, 16 Mar 2021 12:50:38 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/regmask.hpp line 108:
> 
>> 106:          SlotsPerVecY = 8,
>> 107:          SlotsPerVecZ = 16,
>> 108:          SlotsPerRegVMask = X86_ONLY(2) NOT_X86(1)
> 
> It begs for either multiple definitions (like `SlotsPerVec*`) or variable-sized like `SlotsPerVecA`.
> 
> Would like to hear from @XiaohongGong and @nsjian on that.

I am fine with current code. Since we don't have other SlotsPerRegVMask* yet, we will treat it as variable-sized slots for SVE, which is 1.

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