RFR: 8286941: Add mask IR for partial vector operations for ARM SVE

[Xiaohong Gong]

On Wed, 8 Jun 2022 02:34:27 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> src/hotspot/share/opto/matcher.cpp line 2255:
>> 
>>> 2253:     case Op_FmaVF:
>>> 2254:     case Op_MacroLogicV:
>>> 2255:     case Op_LoadVectorMasked:
>> 
>> Why it is removed?
>
> Thanks for looking at this PR! This is removed since we added two combined rules in the aarch64_sve.ad (line-2383) like:
> 
> match(Set dst (VectorLoadMask (LoadVectorMasked mem pg)));
> 
> Setting `Op_LoadVectorMasked` as a root in matcher will make such rules not be matched. I'm also curious why this op is  added here. Does it have any influence if I remove it? Thanks!

@jatin-bhateja, could you please help to check the influence about removing this? Kindly know your feedback about this. Thanks so much!

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

PR: https://git.openjdk.java.net/jdk/pull/9037