[Mesa-dev] [PATCH] i965/nir: Mark const index UBO surfaces as used

[Jordan Justen]

On 2015-10-29 02:17:20, Iago Toral wrote:
> On Thu, 2015-10-29 at 00:50 -0700, Jordan Justen wrote:
> > Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> > ---
> >  src/mesa/drivers/dri/i965/brw_fs_nir.cpp   | 6 ++++--
> >  src/mesa/drivers/dri/i965/brw_vec4_nir.cpp | 6 ++++--
> >  2 files changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> > index 4950ba4..6d69e96 100644
> > --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> > +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> > @@ -1438,8 +1438,10 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
> >        fs_reg surf_index;
> >  
> >        if (const_index) {
> > -         surf_index = fs_reg(stage_prog_data->binding_table.ubo_start +
> > -                             const_index->u[0]);
> > +         unsigned index = stage_prog_data->binding_table.ubo_start +
> > +                          const_index->u[0];
> > +         surf_index = fs_reg(index);
> > +         brw_mark_surface_used(prog_data, index);
> >        } else {
> >           /* The block index is not a constant. Evaluate the index expression
> >            * per-channel and add the base UBO index; we have to select a value
> > diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> > index 0f04f65..efbdaa9 100644
> > --- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> > +++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> > @@ -749,8 +749,10 @@ vec4_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
> >           /* The block index is a constant, so just emit the binding table entry
> >            * as an immediate.
> >            */
> > -         surf_index = src_reg(prog_data->base.binding_table.ubo_start +
> > -                              const_block_index->u[0]);
> > +         unsigned index = prog_data->base.binding_table.ubo_start +
> > +                          const_block_index->u[0];
> > +         surf_index = src_reg(index);
> > +         brw_mark_surface_used(&prog_data->base, index);
> >        } else {
> >           /* The block index is not a constant. Evaluate the index expression
> >            * per-channel and add the base UBO index; we have to select a value
> 
> Is this necessary? As far as I can see, the generator opcodes will mark
> surfaces for which we have a constant index as used, so this should not
> be necessary.

Ah. You are correct.

I was debugging a UBO+SSBO test, and I noticed the discrepancy between
SSBO and UBO, but it appears SSBO has to mark it in brw_*_nir.cpp,
whereas the generator code can also mark it for the constant case for
UBOs.

Maybe we should just handle this in brw_*_nir.cpp for consistency?

-Jordan