Mesa (master): glsl: Optimize (not A) and (not B) into not (A or B).
Matt Turner
mattst88 at kemper.freedesktop.org
Fri Oct 25 17:35:29 UTC 2013
Module: Mesa
Branch: master
Commit: 64c081e8b788ba87c9edc505127b87c3fba47599
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=64c081e8b788ba87c9edc505127b87c3fba47599
Author: Matt Turner <mattst88 at gmail.com>
Date: Wed Oct 23 16:42:34 2013 -0700
glsl: Optimize (not A) and (not B) into not (A or B).
No shader-db changes, but seems like a good idea.
Reviewed-by: Eric Anholt <eric at anholt.net>
---
src/glsl/opt_algebraic.cpp | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 22d2dbf..1351904 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -401,6 +401,15 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
} else if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) {
this->progress = true;
return ir_constant::zero(mem_ctx, ir->type);
+ } 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) and (not B) === not (A or B)
+ */
+ temp = logic_not(logic_or(op_expr[0]->operands[0],
+ op_expr[1]->operands[0]));
+ this->progress = true;
+ return swizzle_if_required(ir, temp);
}
break;
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