[Mesa-dev] [PATCH 10/21] i965: Only add the wpos state reference if we lowered something

[Eero Tamminen]

Hi Jason,

This commit dropped SynMark2 v7 OglShMapPcf performance by 1-2% on GT2 
versions of SKL, KBL and CFL.  It may have improved it by same amount on 
SKL GT4e. Effects on other machines were within normal variation.


	- Eero

On 30.09.2017 00:25, Jason Ekstrand wrote:
> Otherwise, in the ARB program case _mesa_add_state_reference may grow
> the parameter array which will cause brw_nir_setup_arb_uniforms to write
> past the end of the param array because it only looks at the parameter
> list length but the parma array is allocated based on nir->num_uniforms.
> The only reason this hasn't caused us problems is because we are padding
> out the param array for fragment programs unnecessarily.
> ---
>   src/mesa/drivers/dri/i965/brw_program.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
> index ee464fc..7eec6f7 100644
> --- a/src/mesa/drivers/dri/i965/brw_program.c
> +++ b/src/mesa/drivers/dri/i965/brw_program.c
> @@ -88,8 +88,6 @@ brw_create_nir(struct brw_context *brw,
>      }
>      nir_validate_shader(nir);
>   
> -   (void)progress;
> -
>      nir = brw_preprocess_nir(brw->screen->compiler, nir);
>   
>      if (stage == MESA_SHADER_FRAGMENT) {
> @@ -98,10 +96,13 @@ brw_create_nir(struct brw_context *brw,
>            .fs_coord_pixel_center_integer = 1,
>            .fs_coord_origin_upper_left = 1,
>         };
> -      _mesa_add_state_reference(prog->Parameters,
> -                                (gl_state_index *) wpos_options.state_tokens);
>   
> +      progress = false;
>         NIR_PASS(progress, nir, nir_lower_wpos_ytransform, &wpos_options);
> +      if (progress) {
> +         _mesa_add_state_reference(prog->Parameters,
> +                                   (gl_state_index *) wpos_options.state_tokens);
> +      }
>      }
>   
>      NIR_PASS(progress, nir, nir_lower_system_values);
>