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diff --git a/libevmasm/SimplificationRules.h b/libevmasm/SimplificationRules.h
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+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @file SimplificationRules
+ * @author Christian <chris@ethereum.org>
+ * @date 2017
+ * Module for applying replacement rules against Expressions.
+ */
+
+#pragma once
+
+#include <libevmasm/ExpressionClasses.h>
+
+#include <functional>
+#include <vector>
+
+namespace dev
+{
+namespace eth
+{
+
+class Pattern;
+
+/**
+ * Container for all simplification rules.
+ */
+class Rules: public boost::noncopyable
+{
+public:
+	using Expression = ExpressionClasses::Expression;
+
+	Rules();
+
+	/// @returns a pointer to the first matching pattern and sets the match
+	/// groups accordingly.
+	std::pair<Pattern, std::function<Pattern()>> const* findFirstMatch(
+		Expression const& _expr,
+		ExpressionClasses const& _classes
+	);
+
+private:
+	void addRules(std::vector<std::pair<Pattern, std::function<Pattern()>>> const& _rules);
+	void addRule(std::pair<Pattern, std::function<Pattern()>> const& _rule);
+
+	void resetMatchGroups() { m_matchGroups.clear(); }
+
+	std::map<unsigned, Expression const*> m_matchGroups;
+	std::vector<std::pair<Pattern, std::function<Pattern()>>> m_rules[256];
+};
+
+/**
+ * Pattern to match against an expression.
+ * Also stores matched expressions to retrieve them later, for constructing new expressions using
+ * ExpressionTemplate.
+ */
+class Pattern
+{
+public:
+	using Expression = ExpressionClasses::Expression;
+	using Id = ExpressionClasses::Id;
+
+	// Matches a specific constant value.
+	Pattern(unsigned _value): Pattern(u256(_value)) {}
+	// Matches a specific constant value.
+	Pattern(u256 const& _value): m_type(Push), m_requireDataMatch(true), m_data(std::make_shared<u256>(_value)) {}
+	// Matches a specific assembly item type or anything if not given.
+	Pattern(AssemblyItemType _type = UndefinedItem): m_type(_type) {}
+	// Matches a given instruction with given arguments
+	Pattern(Instruction _instruction, std::vector<Pattern> const& _arguments = {});
+	/// Sets this pattern to be part of the match group with the identifier @a _group.
+	/// Inside one rule, all patterns in the same match group have to match expressions from the
+	/// same expression equivalence class.
+	void setMatchGroup(unsigned _group, std::map<unsigned, Expression const*>& _matchGroups);
+	unsigned matchGroup() const { return m_matchGroup; }
+	bool matches(Expression const& _expr, ExpressionClasses const& _classes) const;
+
+	AssemblyItem toAssemblyItem(SourceLocation const& _location) const;
+	std::vector<Pattern> arguments() const { return m_arguments; }
+
+	/// @returns the id of the matched expression if this pattern is part of a match group.
+	Id id() const { return matchGroupValue().id; }
+	/// @returns the data of the matched expression if this pattern is part of a match group.
+	u256 const& d() const { return matchGroupValue().item->data(); }
+
+	std::string toString() const;
+
+	AssemblyItemType type() const { return m_type; }
+	Instruction instruction() const
+	{
+		assertThrow(type() == Operation, OptimizerException, "");
+		return m_instruction;
+	}
+
+private:
+	bool matchesBaseItem(AssemblyItem const* _item) const;
+	Expression const& matchGroupValue() const;
+	u256 const& data() const;
+
+	AssemblyItemType m_type;
+	bool m_requireDataMatch = false;
+	Instruction m_instruction; ///< Only valid if m_type is Operation
+	std::shared_ptr<u256> m_data; ///< Only valid if m_type is not Operation
+	std::vector<Pattern> m_arguments;
+	unsigned m_matchGroup = 0;
+	std::map<unsigned, Expression const*>* m_matchGroups = nullptr;
+};
+
+/**
+ * Template for a new expression that can be built from matched patterns.
+ */
+struct ExpressionTemplate
+{
+	using Expression = ExpressionClasses::Expression;
+	using Id = ExpressionClasses::Id;
+	explicit ExpressionTemplate(Pattern const& _pattern, SourceLocation const& _location);
+	std::string toString() const;
+	bool hasId = false;
+	/// Id of the matched expression, if available.
+	Id id = Id(-1);
+	// Otherwise, assembly item.
+	AssemblyItem item = UndefinedItem;
+	std::vector<ExpressionTemplate> arguments;
+};
+
+}
+}