/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
#pragma once

#if ENABLE(DFG_JIT)

#include "DFGCommon.h"

namespace JSC { namespace DFG {

class Graph;

// Block-local common subexpression elimination. It uses clobberize() for heap
// modeling, which is quite precise. This phase is known to produce big wins on
// a few benchmarks, and is relatively cheap to run.
//
// Note that this phase also gets rid of Identity nodes, which means that it's
// currently not an optional phase. Basically, DFG IR doesn't have use-lists,
// so there is no instantaneous replaceAllUsesWith operation. Instead, you turn
// a node into an Identity and wait for CSE to clean it up.
bool performLocalCSE(Graph&);

// Same, but global. Only works for SSA. This will find common subexpressions
// both in the same block and in any block that dominates the current block. It
// has no limits on how far it will look for load-elimination opportunities.
bool performGlobalCSE(Graph&);

} } // namespace JSC::DFG

#endif // ENABLE(DFG_JIT)