[Mesa-dev] [PATCH] nir/constant_folding: fix incorrect bit-size check

[Juan A. Suarez Romero]

On Wed, 2018-10-31 at 12:18 +0100, Iago Toral Quiroga wrote:
> nir_alu_type_get_type_size takes a type as parameter and we were
> passing a bit-size instead, which did what we wanted by accident,
> since a bit-size of zero matches nir_type_invalid, which has a
> size of 0 too.
> ---


While this patch wasn't nominated to stable, I'm adding it in 18.2 for two
reasons:

- As title suggests, it fixes an issue.
- It is required in order to apply 3595a0abf43 ("nir/constant_folding: Fix
source bit size logic"), which is a candidate for 18.2 stable.


If you do prefer to keep this patch out of 18.2 stable (and thus, also
3595a0abf43), then let me know.

Thanks in advance


	J.A.

>  src/compiler/nir/nir_opt_constant_folding.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/src/compiler/nir/nir_opt_constant_folding.c b/src/compiler/nir/nir_opt_constant_folding.c
> index e5ec5e9583f..c91e7e16855 100644
> --- a/src/compiler/nir/nir_opt_constant_folding.c
> +++ b/src/compiler/nir/nir_opt_constant_folding.c
> @@ -63,10 +63,8 @@ constant_fold_alu_instr(nir_alu_instr *instr, void *mem_ctx)
>        if (!instr->src[i].src.is_ssa)
>           return false;
>  
> -      if (bit_size == 0 &&
> -          !nir_alu_type_get_type_size(nir_op_infos[instr->op].input_sizes[i])) {
> +      if (bit_size == 0 && nir_op_infos[instr->op].input_sizes[i] == 0)
>           bit_size = instr->src[i].src.ssa->bit_size;
> -      }
>  
>        nir_instr *src_instr = instr->src[i].src.ssa->parent_instr;
>