Mesa (master): glsl: Optimize (not A) or (not B) into not (A and B).
Matt Turner
mattst88 at kemper.freedesktop.org
Fri Oct 25 17:35:29 UTC 2013
Module: Mesa
Branch: master
Commit: 65a600f58a7a35016e32e9774560b71f675566fd
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=65a600f58a7a35016e32e9774560b71f675566fd
Author: Matt Turner <mattst88 at gmail.com>
Date: Wed Oct 23 16:40:16 2013 -0700
glsl: Optimize (not A) or (not B) into not (A and B).
A few Serious Sam 3 shaders affected:
instructions in affected programs: 4384 -> 4344 (-0.91%)
Reviewed-by: Eric Anholt <eric at anholt.net>
---
src/glsl/opt_algebraic.cpp | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 37b2f02..22d2dbf 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -32,8 +32,11 @@
#include "ir_visitor.h"
#include "ir_rvalue_visitor.h"
#include "ir_optimization.h"
+#include "ir_builder.h"
#include "glsl_types.h"
+using namespace ir_builder;
+
namespace {
/**
@@ -436,6 +439,15 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
this->progress = true;
return new(mem_ctx) ir_constant(ir->type, &data);
+ } else if (op_expr[0] && op_expr[0]->operation == ir_unop_logic_not &&
+ op_expr[1] && op_expr[1]->operation == ir_unop_logic_not) {
+ /* De Morgan's Law:
+ * (not A) or (not B) === not (A and B)
+ */
+ temp = logic_not(logic_and(op_expr[0]->operands[0],
+ op_expr[1]->operands[0]));
+ this->progress = true;
+ return swizzle_if_required(ir, temp);
}
break;
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