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diff --git a/libyul/optimiser/SSAReverser.h b/libyul/optimiser/SSAReverser.h
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+++ b/libyul/optimiser/SSAReverser.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/optimiser/ASTWalker.h>
+
+namespace yul
+{
+
+class AssignmentCounter;
+
+/**
+ * Reverses the SSA transformation.
+ *
+ * In particular, the SSA transform will rewrite
+ *
+ * 		a := E
+ *
+ * to
+ *
+ * 		let a_1 := E
+ * 		a := a_1
+ *
+ * To undo this kind of transformation, the SSAReverser changes this back to
+ *
+ * 		a := E
+ * 		let a_1 := a
+ *
+ * Secondly, the SSA transform will rewrite
+ *
+ * 		let a := E
+ * to
+ *
+ * 		let a_1 := E
+ * 		let a := a_1
+ *
+ * To undo this kind of transformation, the SSAReverser changes this back to
+ *
+ * 		let a := E
+ * 		let a_1 := a
+ *
+ * 	After that the CSE can replace references of a_1 by references to a,
+ * 	after which the unused pruner can remove the declaration of a_1.
+ *
+ * 	Prerequisites: Disambiguator
+ *
+ */
+class SSAReverser: public ASTModifier
+{
+public:
+	using ASTModifier::operator();
+	void operator()(Block& _block) override;
+
+	static void run(Block& _block);
+private:
+	SSAReverser(AssignmentCounter const& _assignmentCounter): m_assignmentCounter(_assignmentCounter) {}
+	AssignmentCounter const& m_assignmentCounter;
+};
+
+}