[Mesa-dev] [PATCH 1/3] i965/vec4: don't load src on emit_send if it is BAD_FILE

[Francisco Jerez]

Alejandro Piñeiro <apinheiro at igalia.com> writes:

> This can happens if using emit_untyped_atomic for an atomic dec/inc
> ---
>  src/mesa/drivers/dri/i965/brw_vec4_surface_builder.cpp | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_surface_builder.cpp b/src/mesa/drivers/dri/i965/brw_vec4_surface_builder.cpp
> index 28002c5..ba1e670f 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_surface_builder.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_surface_builder.cpp
> @@ -131,9 +131,10 @@ namespace brw {
>                 bld.MOV(offset(payload, n++),
>                         offset(retype(addr, BRW_REGISTER_TYPE_UD), i));
>  
> -            for (unsigned i = 0; i < src_sz; i++)
> -               bld.MOV(offset(payload, n++),
> -                       offset(retype(src, BRW_REGISTER_TYPE_UD), i));
> +            if (src.file != BAD_FILE)
> +               for (unsigned i = 0; i < src_sz; i++)
> +                  bld.MOV(offset(payload, n++),
> +                          offset(retype(src, BRW_REGISTER_TYPE_UD), i));
>  
I don't think this is right, the calculated message size will be off if
src is invalid but src_sz is non-zero.  In cases where the source is not
present you need to make sure you pass src_sz=0 to emit_send() (e.g. in
emit_untyped_atomic).

Thanks.

>              /* Reduce the dynamically uniform surface index to a single
>               * scalar.
> -- 
> 2.5.0
>
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> mesa-dev at lists.freedesktop.org
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