[Mesa-dev] soft fp64 support - main body (glsl/gallium)

[Timothy Arceri]

On 14/03/18 11:04, Dave Airlie wrote:
> On 14 March 2018 at 09:54, Matt Turner <mattst88 at gmail.com> wrote:
>> On Mon, Mar 12, 2018 at 9:24 PM, Dave Airlie <airlied at gmail.com> wrote:
>>> This is the main code for the soft fp64 work. It's mostly Elie's
>>> code with a bunch of changes by me.
>>>
>>> This patchset has all the glsl lowering code. (using float64.glsl,
>>> yes I know checked in files are bad, but not bad enough for anyone
>>> to have solved int64.glsl yet, so we have a precedent).
>>
>> Have you thought about making a NIR backend for R600?
> 
> It would be a lot more work and way too uncertain, I reckon it's taken
> Timothy 6 months to get radeonsi even close with nir, I don't have
> 6 months to spend on getting r600 close, it's backend situation is a lot
> worse than radeonsi.

I don't doubt its a lot of work, but I should note that a chuck of time 
has been ironing out the somewhat rough state the state tracker was in 
in spots and adding the missing stages, nir passes, nir shader cache etc.

Also as the goal was to make the NIR backend better than tgsi I did 
spend a bunch of time working on NIR linking support and related passes 
(added to RADV too). Oh and uniform packing the last couple of days.

Anyway I'm not trying to convince Dave as I'm sure he has a good idea of 
the work involve. Just thought I'd mention this stuff in case anyone 
else has considered working on NIR for r600 and are scared by Daves time 
estimate :)

> 
>>
>> Elie sent patches for lowering fp64 operations in NIR, and it's what
>> I'm going to start from when I do the analogous project for some
>> future Intel hardware. It's sad to duplicate all of this code, much
>> less all of this effort.
> 
> Yes it sucks, but maybe the nir code will get a lot more effort put
> in and I can improve the GLSL code, I'm mostly hoping the GLSL
> code is fire and forget since I doubt anyone in the real world will
> ever use it.
> 
> Dave.
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