[Mesa-stable] [PATCH v2] nir: fix condition propagation when src has a swizzle

[Timothy Arceri]

Hi guys,

When picking this up for 18.3 please note you will also need to grab:

https://cgit.freedesktop.org/mesa/mesa/commit/?id=c7bdda8aa5f1fb1d797512a0a54a032153755c6c

Thanks,
Tim

On 3/11/18 12:37 am, Timothy Arceri wrote:
> We cannot use nir_build_alu() to create the new alu as it has no
> way to know how many components of the src we will use. This
> results in it guessing the max number of components from one of
> its inputs.
> 
> Fixes the following CTS tests:
> 
> dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_frag
> dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_geom
> dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_tessc
> dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_vert
> 
> V2: use nir_src_for_ssa() in clone
> 
> Fixes: 2975422ceb6c ("nir: propagates if condition evaluation down some alu chains")
> ---
>   src/compiler/nir/nir_opt_if.c | 31 ++++++++++++++++++++++++++++++-
>   1 file changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/src/compiler/nir/nir_opt_if.c b/src/compiler/nir/nir_opt_if.c
> index ed93cac9ce9..8a971c43f24 100644
> --- a/src/compiler/nir/nir_opt_if.c
> +++ b/src/compiler/nir/nir_opt_if.c
> @@ -391,6 +391,34 @@ evaluate_if_condition(nir_if *nif, nir_cursor cursor, bool *value)
>      }
>   }
>   
> +static nir_ssa_def *
> +clone_alu_and_replace_src_defs(nir_builder *b, const nir_alu_instr *alu,
> +                               nir_ssa_def **src_defs)
> +{
> +   nir_alu_instr *nalu = nir_alu_instr_create(b->shader, alu->op);
> +   nalu->exact = alu->exact;
> +
> +   nir_ssa_dest_init(&nalu->instr, &nalu->dest.dest,
> +                     alu->dest.dest.ssa.num_components,
> +                     alu->dest.dest.ssa.bit_size, alu->dest.dest.ssa.name);
> +
> +   nalu->dest.saturate = alu->dest.saturate;
> +   nalu->dest.write_mask = alu->dest.write_mask;
> +
> +   for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) {
> +      assert(alu->src[i].src.is_ssa);
> +      nalu->src[i].src = nir_src_for_ssa(src_defs[i]);
> +      nalu->src[i].negate = alu->src[i].negate;
> +      nalu->src[i].abs = alu->src[i].abs;
> +      memcpy(nalu->src[i].swizzle, alu->src[i].swizzle,
> +             sizeof(nalu->src[i].swizzle));
> +   }
> +
> +   nir_builder_instr_insert(b, &nalu->instr);
> +
> +   return &nalu->dest.dest.ssa;;
> +}
> +
>   /*
>    * This propagates if condition evaluation down the chain of some alu
>    * instructions. For example by checking the use of some of the following alu
> @@ -456,7 +484,8 @@ propagate_condition_eval(nir_builder *b, nir_if *nif, nir_src *use_src,
>            def[i] = alu->src[i].src.ssa;
>         }
>      }
> -   nir_ssa_def *nalu = nir_build_alu(b, alu->op, def[0], def[1], def[2], def[3]);
> +
> +   nir_ssa_def *nalu = clone_alu_and_replace_src_defs(b, alu, def);
>   
>      /* Rewrite use to use new alu instruction */
>      nir_src new_src = nir_src_for_ssa(nalu);
>