Mesa (master): glsl: Optimize pow(1.0, X) --> 1.0.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: d6c1d66d3a74e25435b5ebcde208e8049b669120
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=d6c1d66d3a74e25435b5ebcde208e8049b669120

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Sun Jan  5 22:19:42 2014 -0800

glsl: Optimize pow(1.0, X) --> 1.0.

Surprisingly, this helps one vertex shader in 3DMMES.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Matt Turner <mattst88 at gmail.com>

---

 src/glsl/opt_algebraic.cpp |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 05a5899..5e885f7 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -416,6 +416,12 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       }
       break;
 
+   case ir_binop_pow:
+      /* 1^x == 1 */
+      if (is_vec_one(op_const[0]))
+         return op_const[0];
+      break;
+
    case ir_unop_rcp:
       if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp)
 	 return op_expr[0]->operands[0];