[Mesa-dev] [PATCH 13/78] i965/nir/vec4: Implement conditional statements (nir_cf_node_if)

[Jason Ekstrand]

On Fri, Jun 26, 2015 at 1:06 AM, Eduardo Lima Mitev <elima at igalia.com> wrote:
> From: Iago Toral Quiroga <itoral at igalia.com>
>
> The same we do in the FS NIR backend, only that here we need to consider
> the number of components in the condition and adjust the swizzle
> accordingly.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89580
> ---
>  src/mesa/drivers/dri/i965/brw_vec4_nir.cpp | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> index 1ec75ee..d81b6a7 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
> @@ -314,7 +314,28 @@ vec4_visitor::nir_emit_cf_list(exec_list *list)
>  void
>  vec4_visitor::nir_emit_if(nir_if *if_stmt)
>  {
> -   /* @TODO: Not yet implemented */
> +   /* First, put the condition in f0 */
> +   src_reg condition = get_nir_src(if_stmt->condition, BRW_REGISTER_TYPE_D);
> +
> +   int num_components = if_stmt->condition.is_ssa ?
> +      if_stmt->condition.ssa->num_components :
> +      if_stmt->condition.reg.reg->num_components;
> +
> +   condition.swizzle = brw_swizzle_for_size(num_components);
> +
> +   vec4_instruction *inst = emit(MOV(dst_null_d(), condition));
> +   inst->conditional_mod = BRW_CONDITIONAL_NZ;

NIR if statements read only one component by definition.  There's no
need to do this.

> +   emit(IF(BRW_PREDICATE_NORMAL));
> +
> +   nir_emit_cf_list(&if_stmt->then_list);
> +
> +   /* note: if the else is empty, dead CF elimination will remove it */
> +   emit(BRW_OPCODE_ELSE);
> +
> +   nir_emit_cf_list(&if_stmt->else_list);
> +
> +   emit(BRW_OPCODE_ENDIF);
>  }
>
>  void
> --
> 2.1.4
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev