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/*
* Copyright (C) 2016-2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "B3PureCSE.h"
#if ENABLE(B3_JIT)
#include "B3Dominators.h"
#include "B3PhaseScope.h"
#include "B3Value.h"
namespace JSC { namespace B3 {
PureCSE::PureCSE()
{
}
PureCSE::~PureCSE()
{
}
void PureCSE::clear()
{
m_map.clear();
}
Value* PureCSE::findMatch(const ValueKey& key, BasicBlock* block, Dominators& dominators)
{
if (!key)
return nullptr;
auto iter = m_map.find(key);
if (iter == m_map.end())
return nullptr;
for (Value* match : iter->value) {
if (!match->owner)
continue;
if (dominators.dominates(match->owner, block))
return match;
}
return nullptr;
}
bool PureCSE::process(Value* value, Dominators& dominators)
{
if (value->opcode() == Identity || value->isConstant())
return false;
ValueKey key = value->key();
if (!key)
return false;
Matches& matches = m_map.add(key, Matches()).iterator->value;
for (Value* match : matches) {
if (!match->owner)
continue;
if (dominators.dominates(match->owner, value->owner)) {
value->replaceWithIdentity(match);
return true;
}
}
matches.append(value);
return false;
}
bool pureCSE(Procedure& proc)
{
PhaseScope phaseScope(proc, "pureCSE");
Dominators& dominators = proc.dominators();
PureCSE pureCSE;
bool result = false;
for (BasicBlock* block : proc.blocksInPreOrder()) {
for (Value* value : *block) {
result |= value->performSubstitution();
result |= pureCSE.process(value, dominators);
}
}
return result;
}
} } // namespace JSC::B3
#endif // ENABLE(B3_JIT)