Add equivalent function combiner as Yul optimizer step.

libyul/optimiser/EquivalentFunctionCombiner.cpp

@@ -0,0 +1,41 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that combines syntactically equivalent functions.
+ */
+
+#include <libyul/optimiser/EquivalentFunctionCombiner.h>
+#include <libyul/AsmData.h>
+#include <libdevcore/CommonData.h>
+
+using namespace std;
+using namespace dev;
+using namespace yul;
+using namespace dev::solidity;
+
+void EquivalentFunctionCombiner::run(Block& _ast)
+{
+	EquivalentFunctionCombiner{EquivalentFunctionDetector::run(_ast)}(_ast);
+}
+
+void EquivalentFunctionCombiner::operator()(FunctionCall& _funCall)
+{
+	auto it = m_duplicates.find(_funCall.functionName.name);
+	if (it != m_duplicates.end())
+		_funCall.functionName.name = it->second->name;
+	ASTModifier::operator()(_funCall);
+}