[aarch64-port-dev ] RFR (XXL): 8223347: Integration of Vector API (Incubator): AArch64 backend changes

[Viswanathan, Sandhya]

Hi Andrew/Yang,
 
We couldn’t propose Vector API to target in time for JDK 15 and hoping to do so early in JDK 16 timeframe.
The implementation reviews on other components have made good progress. 
We have so far ok to PPT from (runtime, shared compiler changes, x86 backend).
Java API implementation review is in progress.
I wanted to check with you both if we have a go ahead from aarch64 backed point of view.

Best Regards,
Sandhya

-----Original Message-----
From: hotspot-compiler-dev <hotspot-compiler-dev-bounces at openjdk.java.net> On Behalf Of Yang Zhang
Sent: Tuesday, May 26, 2020 7:59 PM
To: Andrew Haley <aph at redhat.com>; Paul Sandoz <paul.sandoz at oracle.com>
Cc: nd <nd at arm.com>; hotspot-compiler-dev at openjdk.java.net; hotspot-dev at openjdk.java.net; core-libs-dev at openjdk.java.net; aarch64-port-dev at openjdk.java.net
Subject: RE: [aarch64-port-dev ] RFR (XXL): 8223347: Integration of Vector API (Incubator): AArch64 backend changes

> But to my earlier question. please: can the new instructions be moved into jdk head first, and then merged into the Panama branch, or not?

The new instructions can be classified as:
1. Instructions that can be matched with NEON instructions directly.
MulVB and SqrtVF have been merged into jdk master already. The patch of AbsV is in review [1].

2. Instructions that Jdk master has middle end support for, but they cannot be matched with NEON instructions directly.
Such as AddReductionVL, MulReductionVL, And/Or/XorReductionV These new instructions can be moved into jdk master first, but for auto-vectorization, the performance might not get improved.
May I have a new patch for these? 

3. Panama/Vector API specific  instructions Such as Load/StoreVector ( 16 bits), VectorReinterpret, VectorMaskCmp, MaxV/MinV, VectorBlend etc. 
These instructions cannot be moved into jdk master first because there isn't middle-end support.

Regards
Yang

[1] https://mail.openjdk.java.net/pipermail/aarch64-port-dev/2020-May/008861.html

-----Original Message-----
From: Andrew Haley <aph at redhat.com>
Sent: Tuesday, May 26, 2020 4:25 PM
To: Yang Zhang <Yang.Zhang at arm.com>; Paul Sandoz <paul.sandoz at oracle.com>
Cc: hotspot-compiler-dev at openjdk.java.net; hotspot-dev at openjdk.java.net; core-libs-dev at openjdk.java.net; aarch64-port-dev at openjdk.java.net; nd <nd at arm.com>
Subject: Re: [aarch64-port-dev ] RFR (XXL): 8223347: Integration of Vector API (Incubator): AArch64 backend changes

On 25/05/2020 09:26, Yang Zhang wrote:
> In jdk master, what we need to do is that writing m4 file for existing 
> vector instructions and placed them to a new file aarch64_neon.ad.
> If no question, I will do it right away.

I'm not entirely sure that such a change is necessary now. In particular, reorganizing the existing vector instructions is IMO excessive, but I admit that it might be an improvement.

But to my earlier question. please: can the new instructions be moved into jdk head first, and then merged into the Panama branch, or not?
It'd help if this was possible.

--
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com> https://keybase.io/andrewhaley
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