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diff --git a/libyul/optimiser/VarDeclPropagator.h b/libyul/optimiser/VarDeclPropagator.h
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+++ b/libyul/optimiser/VarDeclPropagator.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/>.
+*/
+
+#pragma once
+
+#include <libyul/ASTDataForward.h>
+#include <libyul/optimiser/ASTWalker.h>
+#include <libyul/Exceptions.h>
+#include <libsolidity/inlineasm/AsmDataForward.h>
+#include <vector>
+#include <set>
+#include <map>
+
+namespace dev
+{
+namespace yul
+{
+
+/**
+ * Rewrites Assignment statements into VariableDeclaration when the assignment's LHS
+ * variables had no value yet.
+ *
+ * It recursively walks through the AST and moves each declaration of variables to
+ * the first assignment within the same block (if possible)..
+ */
+class VarDeclPropagator: public ASTModifier
+{
+public:
+	using ASTModifier::operator();
+	void operator()(Block& _block) override;
+	void operator()(VariableDeclaration& _varDecl) override;
+	void operator()(Assignment& _assignment) override;
+	void operator()(Identifier& _ident) override;
+
+private:
+	bool allVarNamesUninitialized(std::vector<Identifier> const& _variableNames) const;
+	bool isFullyLazyInitialized(std::vector<Identifier> const& _variableNames) const;
+	VariableDeclaration recreateVariableDeclaration(Assignment& _assignment);
+
+private:
+	/// Holds a list of variables from current Block that have no value assigned yet.
+	std::map<std::string, TypedName> m_emptyVarDecls;
+
+	/// Holds a list variables (and their TypedName) within the current block.
+	std::map<std::string, TypedName> m_lazyInitializedVarDecls;
+};
+
+}
+}