diff --git a/libyul/CMakeLists.txt b/libyul/CMakeLists.txt
index 12d2866c2..65269e9e0 100644
--- a/libyul/CMakeLists.txt
+++ b/libyul/CMakeLists.txt
@@ -154,6 +154,8 @@ add_library(yul
 	optimiser/Suite.h
 	optimiser/SyntacticalEquality.cpp
 	optimiser/SyntacticalEquality.h
+	optimiser/TypeInfo.cpp
+	optimiser/TypeInfo.h
 	optimiser/UnusedPruner.cpp
 	optimiser/UnusedPruner.h
 	optimiser/VarDeclInitializer.cpp
diff --git a/libyul/optimiser/TypeInfo.cpp b/libyul/optimiser/TypeInfo.cpp
new file mode 100644
index 000000000..4b5715baa
--- /dev/null
+++ b/libyul/optimiser/TypeInfo.cpp
@@ -0,0 +1,98 @@
+/*
+	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/>.
+*/
+/**
+ * Helper class that keeps track of the types while performing optimizations.
+ */
+
+#include <libyul/optimiser/TypeInfo.h>
+
+#include <libyul/optimiser/NameCollector.h>
+
+#include <libyul/AsmData.h>
+#include <libyul/Dialect.h>
+
+#include <libsolutil/Visitor.h>
+
+using namespace std;
+using namespace solidity::yul;
+using namespace solidity::util;
+
+class TypeInfo::TypeCollector: public ASTWalker
+{
+public:
+	explicit TypeCollector(Block const& _block)
+	{
+		(*this)(_block);
+	}
+
+	using ASTWalker::operator();
+	void operator()(VariableDeclaration const& _varDecl) override
+	{
+		for (auto const& var: _varDecl.variables)
+			variableTypes[var.name] = var.type;
+	}
+	void operator()(FunctionDefinition const& _funDef) override
+	{
+		ASTWalker::operator()(_funDef);
+
+		auto& funType = functionTypes[_funDef.name];
+		for (auto const arg: _funDef.parameters)
+		{
+			funType.parameters.emplace_back(arg.type);
+			variableTypes[arg.name] = arg.type;
+		}
+		for (auto const ret: _funDef.returnVariables)
+		{
+			funType.returns.emplace_back(ret.type);
+			variableTypes[ret.name] = ret.type;
+		}
+	}
+
+	std::map<YulString, YulString> variableTypes;
+	std::map<YulString, FunctionType> functionTypes;
+};
+
+
+TypeInfo::TypeInfo(Dialect const& _dialect, Block const& _ast):
+	m_dialect(_dialect)
+{
+	TypeCollector types(_ast);
+	m_functionTypes = std::move(types.functionTypes);
+	m_variableTypes = std::move(types.variableTypes);
+}
+
+YulString TypeInfo::typeOf(Expression const& _expression) const
+{
+	return std::visit(GenericVisitor{
+		[&](FunctionCall const& _funCall) {
+			YulString name = _funCall.functionName.name;
+			vector<YulString> const* retTypes = nullptr;
+			if (BuiltinFunction const* fun = m_dialect.builtin(name))
+				retTypes = &fun->returns;
+			else
+				retTypes = &m_functionTypes.at(name).returns;
+			yulAssert(retTypes && retTypes->size() == 1, "Call to typeOf for non-single-value expression.");
+			return retTypes->front();
+		},
+		[&](Identifier const& _identifier) {
+			return m_variableTypes.at(_identifier.name);
+		},
+		[&](Literal const& _literal) {
+			return _literal.type;
+		}
+	}, _expression);
+}
diff --git a/libyul/optimiser/TypeInfo.h b/libyul/optimiser/TypeInfo.h
new file mode 100644
index 000000000..deb537ea3
--- /dev/null
+++ b/libyul/optimiser/TypeInfo.h
@@ -0,0 +1,61 @@
+/*
+	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/>.
+*/
+/**
+ * Helper class that keeps track of the types while performing optimizations.
+ */
+#pragma once
+
+#include <libyul/AsmDataForward.h>
+#include <libyul/YulString.h>
+
+#include <vector>
+#include <map>
+
+namespace solidity::yul
+{
+struct Dialect;
+
+/**
+ * Helper class that keeps track of the types while performing optimizations.
+ *
+ * Only works on disambiguated sources!
+ */
+class TypeInfo
+{
+public:
+	TypeInfo(Dialect const& _dialect, Block const& _ast);
+
+	void setVariableType(YulString _name, YulString _type) { m_variableTypes[_name] = _type; }
+
+	/// @returns the type of an expression that is assumed to return exactly one value.
+	YulString typeOf(Expression const& _expression) const;
+
+private:
+	class TypeCollector;
+
+	struct FunctionType
+	{
+		std::vector<YulString> parameters;
+		std::vector<YulString> returns;
+	};
+
+	Dialect const& m_dialect;
+	std::map<YulString, YulString> m_variableTypes;
+	std::map<YulString, FunctionType> m_functionTypes;
+};
+
+}