From: Eric Anholt <eric@anholt.net>
Date: Sat, 18 Jan 2014 18:57:29 +0000 (-0800)
Subject: glsl: Optimize pow(x, 1) -> x.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d72956790fed5f62b8eea5938ed432544530f7bd;p=mesa.git

glsl: Optimize pow(x, 1) -> x.

total instructions in shared programs: 1627826 -> 1627754 (-0.00%)
instructions in affected programs:     6640 -> 6568 (-1.08%)
GAINED:                                0
LOST:                                  0

(HoN and savage2)

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

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 1e715817f76..953b03c2943 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -520,6 +520,10 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       if (is_vec_one(op_const[0]))
          return op_const[0];
 
+      /* x^1 == x */
+      if (is_vec_one(op_const[1]))
+         return ir->operands[0];
+
       /* pow(2,x) == exp2(x) */
       if (is_vec_two(op_const[0]))
          return expr(ir_unop_exp2, ir->operands[1]);