glsl: Optimize triop_csel with all-true or all-false.

Reviewed-by: Matt Turner <mattst88@gmail.com>

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 7863fe8f9cf472a38fe245b62d689e795542610c..1b4d319366ccf68d1681ce782b2fe02ba3281d4b 100644 (file)
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -571,6 +571,13 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       }
       break;
 
+   case ir_triop_csel:
+      if (is_vec_one(op_const[0]))
+        return ir->operands[1];
+      if (is_vec_zero(op_const[0]))
+        return ir->operands[2];
+      break;
+
    default:
       break;
    }