1 /*
2 * Copyright © 2010 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24 /**
25 * \file lower_noise.cpp
26 * IR lower pass to remove noise opcodes.
27 *
28 * \author Ian Romanick <ian.d.romanick@intel.com>
29 */
30
31 #include "ir.h"
32 #include "ir_rvalue_visitor.h"
33
34 class lower_noise_visitor : public ir_rvalue_visitor {
35 public:
lower_noise_visitor()36 lower_noise_visitor() : progress(false)
37 {
38 /* empty */
39 }
40
handle_rvalue(ir_rvalue ** rvalue)41 void handle_rvalue(ir_rvalue **rvalue)
42 {
43 if (!*rvalue)
44 return;
45
46 ir_expression *expr = (*rvalue)->as_expression();
47 if (!expr)
48 return;
49
50 /* In the future, ir_unop_noise may be replaced by a call to a function
51 * that implements noise. No hardware has a noise instruction.
52 */
53 if (expr->operation == ir_unop_noise) {
54 *rvalue = ir_constant::zero(ralloc_parent(expr), expr->type);
55 this->progress = true;
56 }
57 }
58
59 bool progress;
60 };
61
62
63 bool
lower_noise(exec_list * instructions)64 lower_noise(exec_list *instructions)
65 {
66 lower_noise_visitor v;
67
68 visit_list_elements(&v, instructions);
69
70 return v.progress;
71 }
72