[vectorIntrinsics] RFR: 8254826: Add reduction nodes implementation for Arm SVE

[Andrew Dinn]

On Mon, 19 Oct 2020 01:34:33 GMT, Ningsheng Jian <njian at openjdk.org> wrote:

>> @nsjian my sense is such enhancements are more appropriate in the panama-vector repository until the SVE implementation is mature enough to your and other's satisfaction. In combination, perhaps there are API changes that are useful in this regard. We have the opportunity to think a little more holistically, and AFAICT we have some luxury of time given SVE is still in the early phases of production hardware compared to the other platforms.
>> 
>> Further, ramp down phase 1 of JDK 16 is not that far away. Focusing on the quality of the x86 and AArch64 Neon in the mainline does seem a higher priority to me.
>> 
>> We will re-incubate the Vector API every release if there are changes, a new JEP with updated contents. When SVE support is ready we could update the JEP contents to place it on the same level as x86 and AArch64 Neon.  
>> 
>> Does that sound reasonable?
>
>> @nsjian my sense is such enhancements are more appropriate in the panama-vector repository until the SVE implementation is mature enough to your and other's satisfaction. In combination, perhaps there are API changes that are useful in this regard. We have the opportunity to think a little more holistically, and AFAICT we have some luxury of time given SVE is still in the early phases of production hardware compared to the other platforms.
>> 
>> Further, ramp down phase 1 of JDK 16 is not that far away. Focusing on the quality of the x86 and AArch64 Neon in the mainline does seem a higher priority to me.
>> 
>> We will re-incubate the Vector API every release if there are changes, a new JEP with updated contents. When SVE support is ready we could update the JEP contents to place it on the same level as x86 and AArch64 Neon.
>> 
>> Does that sound reasonable?
> 
> @PaulSandoz Yes, that sounds good to me.

I agree with Paul recommendation that we do this work in Panama and consider upstreaming it for jdk17.

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PR: https://git.openjdk.java.net/panama-vector/pull/13