From 8f890b119eaff88a7fad64abbf183cbcc22edc7a Mon Sep 17 00:00:00 2001 From: Abdiel Janulgue Date: Thu, 19 Jun 2014 22:15:14 -0700 Subject: [PATCH] glsl: Optimize clamp(x, 0, 1) as saturate(x) v2: - Check that the base type is float (Ian Romanick) v3: - Make sure comments reflect that we are doing a commutative operation - Add missing condition where the inner constant is 1.0 and outer constant is 0.0 - Make indexing of operands easier to read (Matt Turner) Reviewed-by: Matt Turner Reviewed-by: Ian Romanick Signed-off-by: Abdiel Janulgue --- src/glsl/opt_algebraic.cpp | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp index ac7514acfd9..4b052933654 100644 --- a/src/glsl/opt_algebraic.cpp +++ b/src/glsl/opt_algebraic.cpp @@ -614,6 +614,42 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir) break; + case ir_binop_min: + case ir_binop_max: + if (ir->type->base_type != GLSL_TYPE_FLOAT) + break; + + /* Replace min(max) operations and its commutative combinations with + * a saturate operation + */ + for (int op = 0; op < 2; op++) { + ir_expression *minmax = op_expr[op]; + ir_constant *outer_const = op_const[1 - op]; + ir_expression_operation op_cond = (ir->operation == ir_binop_max) ? + ir_binop_min : ir_binop_max; + + if (!minmax || !outer_const || (minmax->operation != op_cond)) + continue; + + /* Found a min(max) combination. Now try to see if its operands + * meet our conditions that we can do just a single saturate operation + */ + for (int minmax_op = 0; minmax_op < 2; minmax_op++) { + ir_rvalue *inner_val_a = minmax->operands[minmax_op]; + ir_rvalue *inner_val_b = minmax->operands[1 - minmax_op]; + + if (!inner_val_a || !inner_val_b) + continue; + + /* Found a {min|max} ({max|min} (x, 0.0), 1.0) operation and its variations */ + if ((outer_const->is_one() && inner_val_a->is_zero()) || + (inner_val_a->is_one() && outer_const->is_zero())) + return saturate(inner_val_b); + } + } + + break; + case ir_unop_rcp: if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp) return op_expr[0]->operands[0];