[Mesa-dev] [PATCH] glsl: Use correct mode for split components.

[Jordan Justen]

On 2016-04-25 16:39:21, Kenneth Graunke wrote:
> On Wednesday, April 20, 2016 3:42:01 PM PDT Bas Nieuwenhuizen wrote:
> > The mode should stay the same as the original struct. In
> > particular, shared should not be changed to temporary.
> > 
> > Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> > ---
> >  src/compiler/glsl/opt_structure_splitting.cpp | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/compiler/glsl/opt_structure_splitting.cpp b/src/compiler/
> glsl/opt_structure_splitting.cpp
> > index 0d18a2f..f4c129e 100644
> > --- a/src/compiler/glsl/opt_structure_splitting.cpp
> > +++ b/src/compiler/glsl/opt_structure_splitting.cpp
> > @@ -351,7 +351,7 @@ do_structure_splitting(exec_list *instructions)
> >        entry->components[i] =
> >           new(entry->mem_ctx) ir_variable(type->fields.structure[i].type,
> >                                           name,
> > -                                         ir_var_temporary);
> > +                                         (ir_variable_mode) entry->var->data.mode);
> >        entry->var->insert_before(entry->components[i]);
> >        }
> >  
> > 
> 
> ir_structure_reference_visitor::get_variable_entry bails for uniforms,
> shader inputs/outputs, and SSBOs.  I believe the intention was to bail
> on anything other than auto/temporary variables.  Presumably, we just
> forgot to disallow shared here.
> 
> I think the primary reason for doing that was because uniforms/SSBOs are
> visible via API introspection, and inputs/outputs needed has cross-stage
> implications.
> 
> I don't know much about shared variables, but as long as they're not
> visible via the API, they're probably safe to split.  If so, this patch
> seems reasonable.
> 

The layout of shared variables is not visible to the API. I don't know
of a reason to disable this pass, so we should probably add this
patch.

Is piglit okay with the patch? Does it fix any applications?

-Jordan