Mesa (master): glsl: Optimize lrp(0, y, a) into y * a.

[Matt Turner]

Module: Mesa
Branch: master
Commit: ecc6c3d4ab31c6cd848bce02790000c165a02229
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ecc6c3d4ab31c6cd848bce02790000c165a02229

Author: Matt Turner <mattst88 at gmail.com>
Date:   Mon Feb 24 15:00:44 2014 -0800

glsl: Optimize lrp(0, y, a) into y * a.

Helps two programs in shader-db:

instructions in affected programs:     254 -> 234 (-7.87%)

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

---

 src/glsl/opt_algebraic.cpp |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 1b4d319..28f95a4 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -568,6 +568,8 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
          return ir->operands[1];
       } else if (ir->operands[0]->equals(ir->operands[1])) {
          return ir->operands[0];
+      } else if (is_vec_zero(op_const[0])) {
+         return mul(ir->operands[1], ir->operands[2]);
       }
       break;