1/*
2 * Copyright (C) 2016-2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "B3PureCSE.h"
28
29#if ENABLE(B3_JIT)
30
31#include "B3Dominators.h"
32#include "B3PhaseScope.h"
33#include "B3Value.h"
34#include "B3ValueInlines.h"
35
36namespace JSC { namespace B3 {
37
38PureCSE::PureCSE()
39{
40}
41
42PureCSE::~PureCSE()
43{
44}
45
46void PureCSE::clear()
47{
48 m_map.clear();
49}
50
51Value* PureCSE::findMatch(const ValueKey& key, BasicBlock* block, Dominators& dominators)
52{
53 if (!key)
54 return nullptr;
55
56 auto iter = m_map.find(key);
57 if (iter == m_map.end())
58 return nullptr;
59
60 for (Value* match : iter->value) {
61 if (!match->owner)
62 continue;
63 if (dominators.dominates(match->owner, block))
64 return match;
65 }
66
67 return nullptr;
68}
69
70bool PureCSE::process(Value* value, Dominators& dominators)
71{
72 if (value->opcode() == Identity || value->isConstant())
73 return false;
74
75 ValueKey key = value->key();
76 if (!key)
77 return false;
78
79 Matches& matches = m_map.add(key, Matches()).iterator->value;
80
81 for (Value* match : matches) {
82 if (!match->owner)
83 continue;
84 if (dominators.dominates(match->owner, value->owner)) {
85 value->replaceWithIdentity(match);
86 return true;
87 }
88 }
89
90 matches.append(value);
91 return false;
92}
93
94bool pureCSE(Procedure& proc)
95{
96 PhaseScope phaseScope(proc, "pureCSE");
97
98 Dominators& dominators = proc.dominators();
99 PureCSE pureCSE;
100 bool result = false;
101 for (BasicBlock* block : proc.blocksInPreOrder()) {
102 for (Value* value : *block) {
103 result |= value->performSubstitution();
104 result |= pureCSE.process(value, dominators);
105 }
106 }
107
108 return result;
109}
110
111} } // namespace JSC::B3
112
113#endif // ENABLE(B3_JIT)
114
115