[Mesa-dev] [PATCH 4/9] glsl: Optimize ir_triop_lrp(x, y, a) with a = 0.0f or 1.0f

[Kenneth Graunke]

On 02/19/2013 05:03 PM, Matt Turner wrote:
> ---
>   src/glsl/opt_algebraic.cpp |   16 +++++++++++++---
>   1 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
> index 75948db..952941e 100644
> --- a/src/glsl/opt_algebraic.cpp
> +++ b/src/glsl/opt_algebraic.cpp
> @@ -186,12 +186,12 @@ ir_algebraic_visitor::swizzle_if_required(ir_expression *expr,
>   ir_rvalue *
>   ir_algebraic_visitor::handle_expression(ir_expression *ir)
>   {
> -   ir_constant *op_const[2] = {NULL, NULL};
> -   ir_expression *op_expr[2] = {NULL, NULL};
> +   ir_constant *op_const[3] = {NULL, NULL, NULL};
> +   ir_expression *op_expr[3] = {NULL, NULL, NULL};
>      ir_expression *temp;
>      unsigned int i;
>
> -   assert(ir->get_num_operands() <= 2);
> +   assert(ir->get_num_operands() <= 3);
>      for (i = 0; i < ir->get_num_operands(); i++) {
>         if (ir->operands[i]->type->is_matrix())
>   	 return ir;
> @@ -415,6 +415,16 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
>
>         break;
>
> +   case ir_triop_lrp:

It might be nice to include a comment here, mostly to remind people that 
the operands are x, y, a here (as opposed to y, x, a elsewhere).

Otherwise,
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

> +     if (is_vec_zero(op_const[2])) {
> +        this->progress = true;
> +        return swizzle_if_required(ir, ir->operands[0]);
> +     } else if (is_vec_one(op_const[2])) {
> +        this->progress = true;
> +        return swizzle_if_required(ir, ir->operands[1]);
> +     }
> +     break;
> +
>      default:
>         break;
>      }
>