Mesa (master): glsl: Recognize sat(add(b2f(a), b2f(b))) as a logical OR.

[Matt Turner]

Module: Mesa
Branch: master
Commit: b481ebbe399fdc6386fd52f890ba7c310d333ed5
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=b481ebbe399fdc6386fd52f890ba7c310d333ed5

Author: Matt Turner <mattst88 at gmail.com>
Date:   Wed Mar 18 10:39:38 2015 -0700

glsl: Recognize sat(add(b2f(a), b2f(b))) as a logical OR.

Transform this into b2f(or(a, b)).

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

---

 src/glsl/opt_algebraic.cpp |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 0d1f3fc..98c852a 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -421,6 +421,18 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       break;
    }
 
+   case ir_unop_saturate:
+      if (op_expr[0] && op_expr[0]->operation == ir_binop_add) {
+         ir_expression *b2f_0 = op_expr[0]->operands[0]->as_expression();
+         ir_expression *b2f_1 = op_expr[0]->operands[1]->as_expression();
+
+         if (b2f_0 && b2f_0->operation == ir_unop_b2f &&
+             b2f_1 && b2f_1->operation == ir_unop_b2f) {
+            return b2f(logic_or(b2f_0->operands[0], b2f_1->operands[0]));
+         }
+      }
+      break;
+
    case ir_binop_add:
       if (is_vec_zero(op_const[0]))
 	 return ir->operands[1];