diff --git a/Changelog.md b/Changelog.md
index b88e1a971..6e3602c1f 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -5,6 +5,7 @@ Language Features:
 
 
 Compiler Features:
+ * Yul Optimizer: Remove ``mstore`` and ``sstore`` operations if the slot already contains the same value.
 
 
 
diff --git a/libsolidity/interface/OptimiserSettings.h b/libsolidity/interface/OptimiserSettings.h
index 5317acee4..e1c35e9ea 100644
--- a/libsolidity/interface/OptimiserSettings.h
+++ b/libsolidity/interface/OptimiserSettings.h
@@ -44,7 +44,7 @@ struct OptimiserSettings
 	static char constexpr DefaultYulOptimiserSteps[] =
 		"dhfoDgvulfnTUtnIf"            // None of these can make stack problems worse
 		"["
-			"xa[r]scLM"                // Turn into SSA and simplify
+			"xa[r]EscLM"               // Turn into SSA and simplify
 			"cCTUtTOntnfDIul"          // Perform structural simplification
 			"Lcul"                     // Simplify again
 			"Vcul [j]"                 // Reverse SSA
diff --git a/libyul/CMakeLists.txt b/libyul/CMakeLists.txt
index 16b68535a..fde673e3d 100644
--- a/libyul/CMakeLists.txt
+++ b/libyul/CMakeLists.txt
@@ -120,6 +120,8 @@ add_library(yul
 	optimiser/DeadCodeEliminator.h
 	optimiser/Disambiguator.cpp
 	optimiser/Disambiguator.h
+	optimiser/EqualStoreEliminator.cpp
+	optimiser/EqualStoreEliminator.h
 	optimiser/EquivalentFunctionDetector.cpp
 	optimiser/EquivalentFunctionDetector.h
 	optimiser/EquivalentFunctionCombiner.cpp
diff --git a/libyul/optimiser/EqualStoreEliminator.cpp b/libyul/optimiser/EqualStoreEliminator.cpp
new file mode 100644
index 000000000..c89567868
--- /dev/null
+++ b/libyul/optimiser/EqualStoreEliminator.cpp
@@ -0,0 +1,77 @@
+/*
+	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/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+/**
+ * Optimisation stage that removes mstore and sstore operations if they store the same
+ * value that is already known to be in that slot.
+ */
+
+#include <libyul/optimiser/EqualStoreEliminator.h>
+
+#include <libyul/optimiser/CallGraphGenerator.h>
+#include <libyul/optimiser/OptimizerUtilities.h>
+#include <libyul/optimiser/Semantics.h>
+#include <libyul/optimiser/CallGraphGenerator.h>
+#include <libyul/SideEffects.h>
+#include <libyul/AST.h>
+#include <libyul/Utilities.h>
+
+#include <libevmasm/GasMeter.h>
+#include <libsolutil/Keccak256.h>
+
+#include <limits>
+
+using namespace std;
+using namespace solidity;
+using namespace solidity::util;
+using namespace solidity::evmasm;
+using namespace solidity::yul;
+
+void EqualStoreEliminator::run(OptimiserStepContext const& _context, Block& _ast)
+{
+	EqualStoreEliminator eliminator{
+		_context.dialect,
+		SideEffectsPropagator::sideEffects(_context.dialect, CallGraphGenerator::callGraph(_ast))
+	};
+	eliminator(_ast);
+
+	StatementRemover remover{eliminator.m_pendingRemovals};
+	remover(_ast);
+}
+
+void EqualStoreEliminator::visit(Statement& _statement)
+{
+	// No need to consider potential changes through complex arguments since
+	// isSimpleStore only returns something if the arguments are identifiers.
+	if (ExpressionStatement const* expression = get_if<ExpressionStatement>(&_statement))
+	{
+		if (auto vars = isSimpleStore(StoreLoadLocation::Storage, *expression))
+		{
+			if (auto const* currentValue = valueOrNullptr(m_storage, vars->first))
+				if (*currentValue == vars->second)
+					m_pendingRemovals.insert(&_statement);
+		}
+		else if (auto vars = isSimpleStore(StoreLoadLocation::Memory, *expression))
+		{
+			if (auto const* currentValue = valueOrNullptr(m_memory, vars->first))
+				if (*currentValue == vars->second)
+					m_pendingRemovals.insert(&_statement);
+		}
+	}
+
+	DataFlowAnalyzer::visit(_statement);
+}
diff --git a/libyul/optimiser/EqualStoreEliminator.h b/libyul/optimiser/EqualStoreEliminator.h
new file mode 100644
index 000000000..796fcc538
--- /dev/null
+++ b/libyul/optimiser/EqualStoreEliminator.h
@@ -0,0 +1,60 @@
+/*
+	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/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+/**
+ * Optimisation stage that removes mstore and sstore operations if they store the same
+ * value that is already known to be in that slot.
+ */
+
+#pragma once
+
+#include <libyul/optimiser/DataFlowAnalyzer.h>
+#include <libyul/optimiser/OptimiserStep.h>
+
+namespace solidity::yul
+{
+
+/**
+ * Optimisation stage that removes mstore and sstore operations if they store the same
+ * value that is already known to be in that slot.
+ *
+ * Works best if the code is in SSA form - without literal arguments.
+ *
+ * Prerequisite: Disambiguator, ForLoopInitRewriter.
+ */
+class EqualStoreEliminator: public DataFlowAnalyzer
+{
+public:
+	static constexpr char const* name{"EqualStoreEliminator"};
+	static void run(OptimiserStepContext const&, Block& _ast);
+
+private:
+	EqualStoreEliminator(
+		Dialect const& _dialect,
+		std::map<YulString, SideEffects> _functionSideEffects
+	):
+		DataFlowAnalyzer(_dialect, std::move(_functionSideEffects))
+	{}
+
+protected:
+	using ASTModifier::visit;
+	void visit(Statement& _statement) override;
+
+	std::set<Statement const*> m_pendingRemovals;
+};
+
+}
diff --git a/libyul/optimiser/OptimizerUtilities.cpp b/libyul/optimiser/OptimizerUtilities.cpp
index 23596a745..ba06b2180 100644
--- a/libyul/optimiser/OptimizerUtilities.cpp
+++ b/libyul/optimiser/OptimizerUtilities.cpp
@@ -57,3 +57,18 @@ optional<evmasm::Instruction> yul::toEVMInstruction(Dialect const& _dialect, Yul
 			return builtin->instruction;
 	return nullopt;
 }
+
+void StatementRemover::operator()(Block& _block)
+{
+	util::iterateReplacing(
+		_block.statements,
+		[&](Statement& _statement) -> std::optional<vector<Statement>>
+		{
+			if (m_toRemove.count(&_statement))
+				return {vector<Statement>{}};
+			else
+				return nullopt;
+		}
+	);
+	ASTModifier::operator()(_block);
+}
diff --git a/libyul/optimiser/OptimizerUtilities.h b/libyul/optimiser/OptimizerUtilities.h
index d80b16316..b491e57e1 100644
--- a/libyul/optimiser/OptimizerUtilities.h
+++ b/libyul/optimiser/OptimizerUtilities.h
@@ -25,6 +25,7 @@
 #include <libyul/ASTForward.h>
 #include <libyul/Dialect.h>
 #include <libyul/YulString.h>
+#include <libyul/optimiser/ASTWalker.h>
 
 #include <optional>
 
@@ -48,4 +49,14 @@ bool isRestrictedIdentifier(Dialect const& _dialect, YulString const& _identifie
 /// Helper function that returns the instruction, if the `_name` is a BuiltinFunction
 std::optional<evmasm::Instruction> toEVMInstruction(Dialect const& _dialect, YulString const& _name);
 
+class StatementRemover: public ASTModifier
+{
+public:
+	explicit StatementRemover(std::set<Statement const*> const& _toRemove): m_toRemove(_toRemove) {}
+
+	void operator()(Block& _block) override;
+private:
+	std::set<Statement const*> const& m_toRemove;
+};
+
 }
diff --git a/libyul/optimiser/Suite.cpp b/libyul/optimiser/Suite.cpp
index 4012fa970..0f2194061 100644
--- a/libyul/optimiser/Suite.cpp
+++ b/libyul/optimiser/Suite.cpp
@@ -32,6 +32,7 @@
 #include <libyul/optimiser/DeadCodeEliminator.h>
 #include <libyul/optimiser/FunctionGrouper.h>
 #include <libyul/optimiser/FunctionHoister.h>
+#include <libyul/optimiser/EqualStoreEliminator.h>
 #include <libyul/optimiser/EquivalentFunctionCombiner.h>
 #include <libyul/optimiser/ExpressionSplitter.h>
 #include <libyul/optimiser/ExpressionJoiner.h>
@@ -204,6 +205,7 @@ map<string, unique_ptr<OptimiserStep>> const& OptimiserSuite::allSteps()
 			ConditionalUnsimplifier,
 			ControlFlowSimplifier,
 			DeadCodeEliminator,
+			EqualStoreEliminator,
 			EquivalentFunctionCombiner,
 			ExpressionInliner,
 			ExpressionJoiner,
@@ -244,6 +246,7 @@ map<string, char> const& OptimiserSuite::stepNameToAbbreviationMap()
 		{ConditionalUnsimplifier::name,       'U'},
 		{ControlFlowSimplifier::name,         'n'},
 		{DeadCodeEliminator::name,            'D'},
+		{EqualStoreEliminator::name,          'E'},
 		{EquivalentFunctionCombiner::name,    'v'},
 		{ExpressionInliner::name,             'e'},
 		{ExpressionJoiner::name,              'j'},
diff --git a/libyul/optimiser/UnusedAssignEliminator.cpp b/libyul/optimiser/UnusedAssignEliminator.cpp
index 74dd599a1..273aa6b79 100644
--- a/libyul/optimiser/UnusedAssignEliminator.cpp
+++ b/libyul/optimiser/UnusedAssignEliminator.cpp
@@ -23,6 +23,7 @@
 #include <libyul/optimiser/UnusedAssignEliminator.h>
 
 #include <libyul/optimiser/Semantics.h>
+#include <libyul/optimiser/OptimizerUtilities.h>
 #include <libyul/AST.h>
 
 #include <libsolutil/CommonData.h>
diff --git a/libyul/optimiser/UnusedStoreBase.cpp b/libyul/optimiser/UnusedStoreBase.cpp
index 27700bdf7..73f957ecc 100644
--- a/libyul/optimiser/UnusedStoreBase.cpp
+++ b/libyul/optimiser/UnusedStoreBase.cpp
@@ -23,6 +23,7 @@
 
 #include <libyul/optimiser/Semantics.h>
 #include <libyul/optimiser/OptimiserStep.h>
+#include <libyul/optimiser/OptimizerUtilities.h>
 #include <libyul/AST.h>
 
 #include <libsolutil/CommonData.h>
@@ -156,18 +157,3 @@ void UnusedStoreBase::merge(TrackedStores& _target, vector<TrackedStores>&& _sou
 		merge(_target, move(ts));
 	_source.clear();
 }
-
-void StatementRemover::operator()(Block& _block)
-{
-	util::iterateReplacing(
-		_block.statements,
-		[&](Statement& _statement) -> std::optional<vector<Statement>>
-		{
-			if (m_toRemove.count(&_statement))
-				return {vector<Statement>{}};
-			else
-				return nullopt;
-		}
-	);
-	ASTModifier::operator()(_block);
-}
diff --git a/libyul/optimiser/UnusedStoreBase.h b/libyul/optimiser/UnusedStoreBase.h
index 3bd4e4297..15dccb04a 100644
--- a/libyul/optimiser/UnusedStoreBase.h
+++ b/libyul/optimiser/UnusedStoreBase.h
@@ -105,14 +105,4 @@ protected:
 	size_t m_forLoopNestingDepth = 0;
 };
 
-class StatementRemover: public ASTModifier
-{
-public:
-	explicit StatementRemover(std::set<Statement const*> const& _toRemove): m_toRemove(_toRemove) {}
-
-	void operator()(Block& _block) override;
-private:
-	std::set<Statement const*> const& m_toRemove;
-};
-
 }
diff --git a/test/libyul/YulOptimizerTestCommon.cpp b/test/libyul/YulOptimizerTestCommon.cpp
index cc315c4b9..bb8458d78 100644
--- a/test/libyul/YulOptimizerTestCommon.cpp
+++ b/test/libyul/YulOptimizerTestCommon.cpp
@@ -28,6 +28,7 @@
 #include <libyul/optimiser/ConditionalUnsimplifier.h>
 #include <libyul/optimiser/ConditionalSimplifier.h>
 #include <libyul/optimiser/CommonSubexpressionEliminator.h>
+#include <libyul/optimiser/EqualStoreEliminator.h>
 #include <libyul/optimiser/EquivalentFunctionCombiner.h>
 #include <libyul/optimiser/ExpressionSplitter.h>
 #include <libyul/optimiser/FunctionGrouper.h>
@@ -236,6 +237,11 @@ YulOptimizerTestCommon::YulOptimizerTestCommon(
 			ForLoopInitRewriter::run(*m_context, *m_ast);
 			UnusedAssignEliminator::run(*m_context, *m_ast);
 		}},
+		{"equalStoreEliminator", [&]() {
+			disambiguate();
+			ForLoopInitRewriter::run(*m_context, *m_ast);
+			EqualStoreEliminator::run(*m_context, *m_ast);
+		}},
 		{"ssaPlusCleanup", [&]() {
 			disambiguate();
 			ForLoopInitRewriter::run(*m_context, *m_ast);
diff --git a/test/libyul/yulOptimizerTests/equalStoreEliminator/mstore_with_keccak.yul b/test/libyul/yulOptimizerTests/equalStoreEliminator/mstore_with_keccak.yul
new file mode 100644
index 000000000..395fea6d0
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/equalStoreEliminator/mstore_with_keccak.yul
@@ -0,0 +1,31 @@
+{
+    let var_k := calldataload(0)
+    let _1 := 0x00
+    let _2 := 0x20
+    mstore(_1, var_k)
+    mstore(_2, _1)
+    sstore(keccak256(_1, 0x40), 0x01)
+    mstore(_1, var_k)
+    mstore(_2, _1)
+    sstore(add(keccak256(_1, 0x40), 0x01), 0x03)
+    mstore(_1, var_k)
+    mstore(_2, _1)
+    sstore(add(keccak256(_1, 0x40), 2), 0x04)
+    mstore(_1, var_k)
+    mstore(_2, _1)
+    sstore(add(keccak256(_1, 0x40), 0x03), 2)
+}
+// ----
+// step: equalStoreEliminator
+//
+// {
+//     let var_k := calldataload(0)
+//     let _1 := 0x00
+//     let _2 := 0x20
+//     mstore(_1, var_k)
+//     mstore(_2, _1)
+//     sstore(keccak256(_1, 0x40), 0x01)
+//     sstore(add(keccak256(_1, 0x40), 0x01), 0x03)
+//     sstore(add(keccak256(_1, 0x40), 2), 0x04)
+//     sstore(add(keccak256(_1, 0x40), 0x03), 2)
+// }
diff --git a/test/yulPhaser/Chromosome.cpp b/test/yulPhaser/Chromosome.cpp
index 19616cde0..d3e31b5e8 100644
--- a/test/yulPhaser/Chromosome.cpp
+++ b/test/yulPhaser/Chromosome.cpp
@@ -138,7 +138,7 @@ BOOST_AUTO_TEST_CASE(output_operator_should_create_concise_and_unambiguous_strin
 
 	BOOST_TEST(chromosome.length() == allSteps.size());
 	BOOST_TEST(chromosome.optimisationSteps() == allSteps);
-	BOOST_TEST(toString(chromosome) == "flcCUnDvejsxIOoighFTLMRmVatrpud");
+	BOOST_TEST(toString(chromosome) == "flcCUnDEvejsxIOoighFTLMRrmVatpud");
 }
 
 BOOST_AUTO_TEST_CASE(optimisationSteps_should_translate_chromosomes_genes_to_optimisation_step_names)