i965/nir/vec4: Implement store_output intrinsic

This implementation is based on the current URB setup in vec4_visitor, which
requires the output register to be stored in the output_reg array at variable's
original shader location index. But since nir_lower_io() pass uses the value
in var->data.driver_location, we need to put there var->data.location instead,
prior to calling nir_lower_io(), so that we end up with the correct index
in const_index[0].

The driver_location is not used at all, so this patch also disables the
nir_assign_var_locations pass on non-scalar shaders.

Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
index b241121dac7..4f7335024a4 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -106,13 +106,16 @@ brw_create_nir(struct brw_context *brw,
                                             &nir->num_direct_uniforms,
                                             &nir->num_uniforms,
                                             is_scalar);
+      nir_assign_var_locations(&nir->outputs, &nir->num_outputs, is_scalar);
    } else {
       nir_assign_var_locations(&nir->uniforms,
                                &nir->num_uniforms,
                                is_scalar);
+
+      foreach_list_typed(nir_variable, var, node, &nir->outputs)
+         var->data.driver_location = var->data.location;
    }
    nir_assign_var_locations(&nir->inputs, &nir->num_inputs, is_scalar);
-   nir_assign_var_locations(&nir->outputs, &nir->num_outputs, is_scalar);
 
    nir_lower_io(nir, is_scalar);