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

Thu Mar 18 11:57:53 UTC 2021

On Wed, 17 Mar 2021 04:11:53 GMT, Ningsheng Jian <njian at openjdk.org> wrote:

>> 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.

Ok, maybe set `SlotsPerRegVMask = 2` unconditionally then?

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