RFR: 8256318: AArch64: Add support for floating-point absolute difference [v3]

[Andrew Haley]

On 11/16/20 3:15 AM, Ningsheng Jian wrote:
> On Mon, 16 Nov 2020 02:51:05 GMT, Dong Bo <dongbo at openjdk.org> wrote:
> 
>> But I feel a little bit unconsistent that only the new fabd is added into aarch64_neon.ad,
>> while other NEON intructions (i.e. fabs, fsub, fdiv, fsqrt, etc) are still in aarch64.ad.
>> And moving them all from aarch64.ad to aarch64_neon.ad deviates far from this patch.
> 
> Yes, I think when we introduced aarch64_neon.ad (m4), we just tried to keep that patch simple and would move other vector rules in future patches. Maybe Andrew can comment on this?

I wonder: I'm not sure if we should do the lot in one bang.

I can't quite figure out the best thing to do. It'll be tricky to move
all of the SIMD instructions, but I guess it's the best thing to do. It'll
make backports hard, but we don't see many in this area.

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