[Mesa-dev] [PATCH] glsl/dead_builin_varyings: Fix gl_FragData array lowering

[Iago Toral]

On Mon, 2015-11-30 at 09:56 +0200, Tapani Pälli wrote:
> Hi;
> 
> On 11/27/2015 02:14 PM, Iago Toral Quiroga wrote:
> > The current implementation looks for array dereferences on gl_FragData and
> > immediately then proceeds to lower them, however this is not enough because
> > we can have array access on vector variables too, like in this code:
> >
> > out vec4 color;
> > void main()
> > {
> >     int i;
> >     for (i = 0; i < 4; i++)
> >        color[i] = 1.0;
> > }
> >
> > Fix it by making sure that the actual variable being dereferenced is an array.
> >
> > Fixes a crash in:
> > spec/arb_gpu_shader_fp64/execution/built-in-functions/fs-ldexp-dvec4.shader_test
> 
> Instead of asserting in IR validation now we assert in backend because 
> array 'should have been lowered' .. is there some other patches that 
> should be bundled together with this to make it work?

Yes, notice that this is a fp64 test, which is not implemented in i965
yet. There is a development branch here if you want to try it:

https://github.com/Igalia/mesa/tree/i965-fp64-v5-testing

and with that branch (which includes this patch) the test does not crash
any more (it still fails though).

Iago

> > ---
> >   src/glsl/opt_dead_builtin_varyings.cpp | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/src/glsl/opt_dead_builtin_varyings.cpp b/src/glsl/opt_dead_builtin_varyings.cpp
> > index 68b70ee..5387113 100644
> > --- a/src/glsl/opt_dead_builtin_varyings.cpp
> > +++ b/src/glsl/opt_dead_builtin_varyings.cpp
> > @@ -85,7 +85,7 @@ public:
> >      {
> >         ir_variable *var = ir->variable_referenced();
> >
> > -      if (!var || var->data.mode != this->mode)
> > +      if (!var || var->data.mode != this->mode || !var->type->is_array())
> >            return visit_continue;
> >
> >         if (this->find_frag_outputs && var->data.location == FRAG_RESULT_DATA0) {
> >
>