RFR: 8262355: Support for AVX-512 opmask register allocation. [v3]

[Jatin Bhateja]

On Mon, 15 Mar 2021 09:13:47 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8262355: Creating a new ideal type TypeVectMask for mask generating nodes.
>
> src/hotspot/share/opto/type.cpp line 2417:
> 
>> 2415: const TypeVect *TypeVect::makemask(const BasicType elem_bt, uint length) {
>> 2416:   if (Matcher::has_predicated_vectors()) {
>> 2417:     return (TypeVect*)(new TypeVectMask(get_const_basic_type(T_BOOLEAN), MaxVectorSize))->hashcons();
> 
> Do you mean the `TypeVectMask` only saves the `T_BOOLEAN` as the basic type for all the mask type?

Yes,  that is correct for targets which do not support predicate registers flow differs and a TypeVect matches with type of vector register.

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