/*
 * Copyright (C) 2011, 2014 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
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 * 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
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 */

#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)
