[Mesa-stable] [Mesa-dev] [PATCH] intel: compiler: remove dead local variables at optimization pass

[Andres Gomez]

Lionel, should we also include this in the stable queues ?


On Mon, 2018-09-03 at 16:47 +0100, Lionel Landwerlin wrote:
> We're hitting an assert in gfxbench because one of the local variable
> is a sampler (according to Jason this isn't valid) :
> 
> testfw_app: ../src/compiler/nir_types.cpp:551: void glsl_get_natural_size_align_bytes(const glsl_type*, unsigned int*, unsigned int*): Assertion `!"type does not have a natural size"' failed.
> 
> Since this particular variable isn't used and it can be eliminated by
> removing unused local variables in the optimization pass. This makes
> sense also for valid local variables.
> 
> v2: Move additional local variable removal out of optimization loop,
>     but before large constant removal (Jason/Lionel)
> 
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> ---
>  src/intel/compiler/brw_nir.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/intel/compiler/brw_nir.c b/src/intel/compiler/brw_nir.c
> index ef5034d1e1e..8c1bcb99f8c 100644
> --- a/src/intel/compiler/brw_nir.c
> +++ b/src/intel/compiler/brw_nir.c
> @@ -673,6 +673,11 @@ brw_preprocess_nir(const struct brw_compiler *compiler, nir_shader *nir)
>  
>     nir = brw_nir_optimize(nir, compiler, is_scalar, true);
>  
> +   /* Workaround Gfxbench unused local sampler variable which will trigger an
> +    * assert in the opt_large_constants pass.
> +    */
> +   OPT(nir_remove_dead_variables, nir_var_local);
> +
>     /* This needs to be run after the first optimization pass but before we
>      * lower indirect derefs away
>      */
-- 
Br,

Andres