[vectorIntrinsics] Issue to VectorAPI "selectFrom" for byte type with Arm SVE 2048-bits

[Paul Sandoz]

> On Nov 5, 2020, at 7:51 PM, Xiaohong Gong <Xiaohong.Gong at arm.com> wrote:
> 
>> Hi,
>> 
>> No plans currently for more exotic shapes and interoperation of vectors with different but compatible shapes. It’s not clear to me whether many cases be handled by composition on top of the Vector API, rather than embedding more deeply into the Vector API itself.
>> 
>> Near term I think it may be possible to focus on the max byte implementations. It will be interesting to see what vector shape (bit size) SVE hardware implementations choose. Do you have any sense on that?
> 
> Agree that we can focus on max byte implementations in the short term. I don't see any Arm implementation hardware will exceed byte index limit in near future. And maybe we can fix that when we have hardware or a good solution?

Yes.


> 
>> 
>> Further, I think we need to focus on masking and loops.
>> 
> 
> Do you have any plan on this? I am also going to work on masking support, as that's the key feature for SVE.  Thanks!
> 

No specific plan, right now. I don’t have a strong sense of the dividing line between agnostic and platform specific C2 enhancements, but there should be some similarities across platforms for a mask loop induction variable. It requires some prototyping.

Paul.