[Mesa-dev] [PATCH shader-db 2/2] run: Mark shaders with only one stage as separable.

[Kenneth Graunke]

On Tuesday, July 26, 2016 12:59:37 PM PDT Timothy Arceri wrote:
> On Mon, 2016-07-25 at 16:54 -0700, Kenneth Graunke wrote:
> > There are a couple cases where a single shader might happen:
> > 
> > - compute shaders
> >   (only one stage, no inputs and outputs; separable shouldn't matter)
> > - vertex shaders with transform feedback
> >   (we want to retain outputs, but transform feedback varyings are
> >    specified via the API, not the shader - setting SSO fixes this)
> 
> ARB_enhanced_layouts does allow these to be specified in shader
> although that might be difficult to recognise.

Right, I was thinking of pre-4.4 shaders.  I think we have a couple
of shaders using transform feedback, but I was mostly trying to think
of cases where having a single stage (other than compute) would actually
be useful.

> Also this will retain all varyings not just xfb varyings maybe we
> should capture xfb varyings when dumping shaders as this also doesn't
> fix xfb for say vs->gs or even vs->fs. Anyway just a thought, I guess
> this patch probably does make things better than worse.

Yeah, we could definitely do better for xfb.  The main point was to
make Marek's life easier by supporting older shaders that don't have
"SSO ENABLED" set.  I also debated about writing a script to find old
shaders and add SSO ENABLED to them, so we could just do that once,
and not carry a hack for it.  But then I figured this would make a
few other situations a bit better, too, so I'd just go with it.

--Ken
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