Restructure test folders

1 files changed, 820 insertions, 0 deletions

diff --git a/libsolidity/SolidityOptimizer.cpp b/libsolidity/SolidityOptimizer.cpp
new file mode 100644
index 00000000..8ab1de8f
--- /dev/null
+++ b/libsolidity/SolidityOptimizer.cpp
@@ -0,0 +1,820 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum 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.
+
+	cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @author Christian <c@ethdev.com>
+ * @date 2014
+ * Tests for the Solidity optimizer.
+ */
+
+#if ETH_SOLIDITY
+
+#include <string>
+#include <tuple>
+#include <boost/test/unit_test.hpp>
+#include <boost/lexical_cast.hpp>
+#include <test/libsolidity/solidityExecutionFramework.h>
+#include <libevmcore/CommonSubexpressionEliminator.h>
+#include <libevmcore/ControlFlowGraph.h>
+#include <libevmcore/Assembly.h>
+
+using namespace std;
+using namespace dev::eth;
+
+namespace dev
+{
+namespace solidity
+{
+namespace test
+{
+
+class OptimizerTestFramework: public ExecutionFramework
+{
+public:
+	OptimizerTestFramework() { }
+	/// Compiles the source code with and without optimizing.
+	void compileBothVersions(
+		std::string const& _sourceCode,
+		u256 const& _value = 0,
+		std::string const& _contractName = ""
+	)
+	{
+		m_optimize = false;
+		bytes nonOptimizedBytecode = compileAndRun(_sourceCode, _value, _contractName);
+		m_nonOptimizedContract = m_contractAddress;
+		m_optimize = true;
+		bytes optimizedBytecode = compileAndRun(_sourceCode, _value, _contractName);
+		size_t nonOptimizedSize = 0;
+		eth::eachInstruction(nonOptimizedBytecode, [&](Instruction, u256 const&) {
+			nonOptimizedSize++;
+		});
+		size_t optimizedSize = 0;
+		eth::eachInstruction(optimizedBytecode, [&](Instruction, u256 const&) {
+			optimizedSize++;
+		});
+		BOOST_CHECK_MESSAGE(
+			nonOptimizedSize > optimizedSize,
+			"Optimizer did not reduce bytecode size."
+		);
+		m_optimizedContract = m_contractAddress;
+	}
+
+	template <class... Args>
+	void compareVersions(std::string _sig, Args const&... _arguments)
+	{
+		m_contractAddress = m_nonOptimizedContract;
+		bytes nonOptimizedOutput = callContractFunction(_sig, _arguments...);
+		m_contractAddress = m_optimizedContract;
+		bytes optimizedOutput = callContractFunction(_sig, _arguments...);
+		BOOST_CHECK_MESSAGE(nonOptimizedOutput == optimizedOutput, "Computed values do not match."
+							"\nNon-Optimized: " + toHex(nonOptimizedOutput) +
+							"\nOptimized:     " + toHex(optimizedOutput));
+	}
+
+	AssemblyItems getCSE(AssemblyItems const& _input)
+	{
+		eth::CommonSubexpressionEliminator cse;
+		BOOST_REQUIRE(cse.feedItems(_input.begin(), _input.end()) == _input.end());
+		return cse.getOptimizedItems();
+	}
+
+	void checkCSE(AssemblyItems const& _input, AssemblyItems const& _expectation)
+	{
+		AssemblyItems output = getCSE(_input);
+		BOOST_CHECK_EQUAL_COLLECTIONS(_expectation.begin(), _expectation.end(), output.begin(), output.end());
+	}
+
+	void checkCFG(AssemblyItems const& _input, AssemblyItems const& _expectation)
+	{
+		AssemblyItems output = _input;
+		// Running it four times should be enough for these tests.
+		for (unsigned i = 0; i < 4; ++i)
+		{
+			eth::ControlFlowGraph cfg(output);
+			output = cfg.optimisedItems();
+		}
+		BOOST_CHECK_EQUAL_COLLECTIONS(_expectation.begin(), _expectation.end(), output.begin(), output.end());
+	}
+
+protected:
+	Address m_optimizedContract;
+	Address m_nonOptimizedContract;
+};
+
+BOOST_FIXTURE_TEST_SUITE(SolidityOptimizer, OptimizerTestFramework)
+
+BOOST_AUTO_TEST_CASE(smoke_test)
+{
+	char const* sourceCode = R"(
+		contract test {
+			function f(uint a) returns (uint b) {
+				return a;
+			}
+		})";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)", u256(7));
+}
+
+BOOST_AUTO_TEST_CASE(identities)
+{
+	char const* sourceCode = R"(
+		contract test {
+			function f(int a) returns (int b) {
+				return int(0) | (int(1) * (int(0) ^ (0 + a)));
+			}
+		})";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)", u256(0x12334664));
+}
+
+BOOST_AUTO_TEST_CASE(unused_expressions)
+{
+	char const* sourceCode = R"(
+		contract test {
+			uint data;
+			function f() returns (uint a, uint b) {
+				10 + 20;
+				data;
+			}
+		})";
+	compileBothVersions(sourceCode);
+	compareVersions("f()");
+}
+
+BOOST_AUTO_TEST_CASE(constant_folding_both_sides)
+{
+	// if constants involving the same associative and commutative operator are applied from both
+	// sides, the operator should be applied only once, because the expression compiler pushes
+	// literals as late as possible
+	char const* sourceCode = R"(
+		contract test {
+			function f(uint x) returns (uint y) {
+				return 98 ^ (7 * ((1 | (x | 1000)) * 40) ^ 102);
+			}
+		})";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)");
+}
+
+BOOST_AUTO_TEST_CASE(storage_access)
+{
+	char const* sourceCode = R"(
+		contract test {
+			uint8[40] data;
+			function f(uint x) returns (uint y) {
+				data[2] = data[7] = uint8(x);
+				data[4] = data[2] * 10 + data[3];
+			}
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)");
+}
+
+BOOST_AUTO_TEST_CASE(array_copy)
+{
+	char const* sourceCode = R"(
+		contract test {
+			bytes2[] data1;
+			bytes5[] data2;
+			function f(uint x) returns (uint l, uint y) {
+				for (uint i = 0; i < msg.data.length; ++i)
+					data1[i] = msg.data[i];
+				data2 = data1;
+				l = data2.length;
+				y = uint(data2[x]);
+			}
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)", 0);
+	compareVersions("f(uint256)", 10);
+	compareVersions("f(uint256)", 36);
+}
+
+BOOST_AUTO_TEST_CASE(function_calls)
+{
+	char const* sourceCode = R"(
+		contract test {
+			function f1(uint x) returns (uint) { return x*x; }
+			function f(uint x) returns (uint) { return f1(7+x) - this.f1(x**9); }
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)", 0);
+	compareVersions("f(uint256)", 10);
+	compareVersions("f(uint256)", 36);
+}
+
+BOOST_AUTO_TEST_CASE(cse_intermediate_swap)
+{
+	eth::CommonSubexpressionEliminator cse;
+	AssemblyItems input{
+		Instruction::SWAP1, Instruction::POP, Instruction::ADD, u256(0), Instruction::SWAP1,
+		Instruction::SLOAD, Instruction::SWAP1, u256(100), Instruction::EXP, Instruction::SWAP1,
+		Instruction::DIV, u256(0xff), Instruction::AND
+	};
+	BOOST_REQUIRE(cse.feedItems(input.begin(), input.end()) == input.end());
+	AssemblyItems output = cse.getOptimizedItems();
+	BOOST_CHECK(!output.empty());
+}
+
+BOOST_AUTO_TEST_CASE(cse_negative_stack_access)
+{
+	AssemblyItems input{Instruction::DUP2, u256(0)};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_negative_stack_end)
+{
+	AssemblyItems input{Instruction::ADD};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_intermediate_negative_stack)
+{
+	AssemblyItems input{Instruction::ADD, u256(1), Instruction::DUP1};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_pop)
+{
+	checkCSE({Instruction::POP}, {Instruction::POP});
+}
+
+BOOST_AUTO_TEST_CASE(cse_unneeded_items)
+{
+	AssemblyItems input{
+		Instruction::ADD,
+		Instruction::SWAP1,
+		Instruction::POP,
+		u256(7),
+		u256(8),
+	};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_constant_addition)
+{
+	AssemblyItems input{u256(7), u256(8), Instruction::ADD};
+	checkCSE(input, {u256(7 + 8)});
+}
+
+BOOST_AUTO_TEST_CASE(cse_invariants)
+{
+	AssemblyItems input{
+		Instruction::DUP1,
+		Instruction::DUP1,
+		u256(0),
+		Instruction::OR,
+		Instruction::OR
+	};
+	checkCSE(input, {Instruction::DUP1});
+}
+
+BOOST_AUTO_TEST_CASE(cse_subself)
+{
+	checkCSE({Instruction::DUP1, Instruction::SUB}, {Instruction::POP, u256(0)});
+}
+
+BOOST_AUTO_TEST_CASE(cse_subother)
+{
+	checkCSE({Instruction::SUB}, {Instruction::SUB});
+}
+
+BOOST_AUTO_TEST_CASE(cse_double_negation)
+{
+	checkCSE({Instruction::DUP5, Instruction::NOT, Instruction::NOT}, {Instruction::DUP5});
+}
+
+BOOST_AUTO_TEST_CASE(cse_associativity)
+{
+	AssemblyItems input{
+		Instruction::DUP1,
+		Instruction::DUP1,
+		u256(0),
+		Instruction::OR,
+		Instruction::OR
+	};
+	checkCSE(input, {Instruction::DUP1});
+}
+
+BOOST_AUTO_TEST_CASE(cse_associativity2)
+{
+	AssemblyItems input{
+		u256(0),
+		Instruction::DUP2,
+		u256(2),
+		u256(1),
+		Instruction::DUP6,
+		Instruction::ADD,
+		u256(2),
+		Instruction::ADD,
+		Instruction::ADD,
+		Instruction::ADD,
+		Instruction::ADD
+	};
+	checkCSE(input, {Instruction::DUP2, Instruction::DUP2, Instruction::ADD, u256(5), Instruction::ADD});
+}
+
+BOOST_AUTO_TEST_CASE(cse_storage)
+{
+	AssemblyItems input{
+		u256(0),
+		Instruction::SLOAD,
+		u256(0),
+		Instruction::SLOAD,
+		Instruction::ADD,
+		u256(0),
+		Instruction::SSTORE
+	};
+	checkCSE(input, {
+		u256(0),
+		Instruction::DUP1,
+		Instruction::SLOAD,
+		Instruction::DUP1,
+		Instruction::ADD,
+		Instruction::SWAP1,
+		Instruction::SSTORE
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_noninterleaved_storage)
+{
+	// two stores to the same location should be replaced by only one store, even if we
+	// read in the meantime
+	AssemblyItems input{
+		u256(7),
+		Instruction::DUP2,
+		Instruction::SSTORE,
+		Instruction::DUP1,
+		Instruction::SLOAD,
+		u256(8),
+		Instruction::DUP3,
+		Instruction::SSTORE
+	};
+	checkCSE(input, {
+		u256(8),
+		Instruction::DUP2,
+		Instruction::SSTORE,
+		u256(7)
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_interleaved_storage)
+{
+	// stores and reads to/from two unknown locations, should not optimize away the first store
+	AssemblyItems input{
+		u256(7),
+		Instruction::DUP2,
+		Instruction::SSTORE, // store to "DUP1"
+		Instruction::DUP2,
+		Instruction::SLOAD, // read from "DUP2", might be equal to "DUP1"
+		u256(0),
+		Instruction::DUP3,
+		Instruction::SSTORE // store different value to "DUP1"
+	};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_interleaved_storage_same_value)
+{
+	// stores and reads to/from two unknown locations, should not optimize away the first store
+	// but it should optimize away the second, since we already know the value will be the same
+	AssemblyItems input{
+		u256(7),
+		Instruction::DUP2,
+		Instruction::SSTORE, // store to "DUP1"
+		Instruction::DUP2,
+		Instruction::SLOAD, // read from "DUP2", might be equal to "DUP1"
+		u256(6),
+		u256(1),
+		Instruction::ADD,
+		Instruction::DUP3,
+		Instruction::SSTORE // store same value to "DUP1"
+	};
+	checkCSE(input, {
+		u256(7),
+		Instruction::DUP2,
+		Instruction::SSTORE,
+		Instruction::DUP2,
+		Instruction::SLOAD
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_interleaved_storage_at_known_location)
+{
+	// stores and reads to/from two known locations, should optimize away the first store,
+	// because we know that the location is different
+	AssemblyItems input{
+		u256(0x70),
+		u256(1),
+		Instruction::SSTORE, // store to 1
+		u256(2),
+		Instruction::SLOAD, // read from 2, is different from 1
+		u256(0x90),
+		u256(1),
+		Instruction::SSTORE // store different value at 1
+	};
+	checkCSE(input, {
+		u256(2),
+		Instruction::SLOAD,
+		u256(0x90),
+		u256(1),
+		Instruction::SSTORE
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_interleaved_storage_at_known_location_offset)
+{
+	// stores and reads to/from two locations which are known to be different,
+	// should optimize away the first store, because we know that the location is different
+	AssemblyItems input{
+		u256(0x70),
+		Instruction::DUP2,
+		u256(1),
+		Instruction::ADD,
+		Instruction::SSTORE, // store to "DUP1"+1
+		Instruction::DUP1,
+		u256(2),
+		Instruction::ADD,
+		Instruction::SLOAD, // read from "DUP1"+2, is different from "DUP1"+1
+		u256(0x90),
+		Instruction::DUP3,
+		u256(1),
+		Instruction::ADD,
+		Instruction::SSTORE // store different value at "DUP1"+1
+	};
+	checkCSE(input, {
+		u256(2),
+		Instruction::DUP2,
+		Instruction::ADD,
+		Instruction::SLOAD,
+		u256(0x90),
+		u256(1),
+		Instruction::DUP4,
+		Instruction::ADD,
+		Instruction::SSTORE
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_interleaved_memory_at_known_location_offset)
+{
+	// stores and reads to/from two locations which are known to be different,
+	// should not optimize away the first store, because the location overlaps with the load,
+	// but it should optimize away the second, because we know that the location is different by 32
+	AssemblyItems input{
+		u256(0x50),
+		Instruction::DUP2,
+		u256(2),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x50
+		u256(0x60),
+		Instruction::DUP2,
+		u256(32),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x60
+		Instruction::DUP1,
+		Instruction::MLOAD, // read from "DUP1"
+		u256(0x70),
+		Instruction::DUP3,
+		u256(32),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x70
+		u256(0x80),
+		Instruction::DUP3,
+		u256(2),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x80
+	};
+	// If the actual code changes too much, we could also simply check that the output contains
+	// exactly 3 MSTORE and exactly 1 MLOAD instruction.
+	checkCSE(input, {
+		u256(0x50),
+		u256(2),
+		Instruction::DUP3,
+		Instruction::ADD,
+		Instruction::SWAP1,
+		Instruction::DUP2,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x50
+		Instruction::DUP2,
+		Instruction::MLOAD, // read from "DUP1"
+		u256(0x70),
+		u256(32),
+		Instruction::DUP5,
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x70
+		u256(0x80),
+		Instruction::SWAP1,
+		Instruction::SWAP2,
+		Instruction::MSTORE // ["DUP1"+2] = 0x80
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_deep_stack)
+{
+	AssemblyItems input{
+		Instruction::ADD,
+		Instruction::SWAP1,
+		Instruction::POP,
+		Instruction::SWAP8,
+		Instruction::POP,
+		Instruction::SWAP8,
+		Instruction::POP,
+		Instruction::SWAP8,
+		Instruction::SWAP5,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+	};
+	checkCSE(input, {
+		Instruction::SWAP4,
+		Instruction::SWAP12,
+		Instruction::SWAP3,
+		Instruction::SWAP11,
+		Instruction::POP,
+		Instruction::SWAP1,
+		Instruction::SWAP3,
+		Instruction::ADD,
+		Instruction::SWAP8,
+		Instruction::POP,
+		Instruction::SWAP6,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+		Instruction::POP,
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_jumpi_no_jump)
+{
+	AssemblyItems input{
+		u256(0),
+		u256(1),
+		Instruction::DUP2,
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMPI
+	};
+	checkCSE(input, {
+		u256(0),
+		u256(1)
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_jumpi_jump)
+{
+	AssemblyItems input{
+		u256(1),
+		u256(1),
+		Instruction::DUP2,
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMPI
+	};
+	checkCSE(input, {
+		u256(1),
+		Instruction::DUP1,
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMP
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_empty_sha3)
+{
+	AssemblyItems input{
+		u256(0),
+		Instruction::DUP2,
+		Instruction::SHA3
+	};
+	checkCSE(input, {
+		u256(sha3(bytesConstRef()))
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_partial_sha3)
+{
+	AssemblyItems input{
+		u256(0xabcd) << (256 - 16),
+		u256(0),
+		Instruction::MSTORE,
+		u256(2),
+		u256(0),
+		Instruction::SHA3
+	};
+	checkCSE(input, {
+		u256(0xabcd) << (256 - 16),
+		u256(0),
+		Instruction::MSTORE,
+		u256(sha3(bytes{0xab, 0xcd}))
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_sha3_twice_same_location)
+{
+	// sha3 twice from same dynamic location
+	AssemblyItems input{
+		Instruction::DUP2,
+		Instruction::DUP1,
+		Instruction::MSTORE,
+		u256(64),
+		Instruction::DUP2,
+		Instruction::SHA3,
+		u256(64),
+		Instruction::DUP3,
+		Instruction::SHA3
+	};
+	checkCSE(input, {
+		Instruction::DUP2,
+		Instruction::DUP1,
+		Instruction::MSTORE,
+		u256(64),
+		Instruction::DUP2,
+		Instruction::SHA3,
+		Instruction::DUP1
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_sha3_twice_same_content)
+{
+	// sha3 twice from different dynamic location but with same content
+	AssemblyItems input{
+		Instruction::DUP1,
+		u256(0x80),
+		Instruction::MSTORE, // m[128] = DUP1
+		u256(0x20),
+		u256(0x80),
+		Instruction::SHA3, // sha3(m[128..(128+32)])
+		Instruction::DUP2,
+		u256(12),
+		Instruction::MSTORE, // m[12] = DUP1
+		u256(0x20),
+		u256(12),
+		Instruction::SHA3 // sha3(m[12..(12+32)])
+	};
+	checkCSE(input, {
+		u256(0x80),
+		Instruction::DUP2,
+		Instruction::DUP2,
+		Instruction::MSTORE,
+		u256(0x20),
+		Instruction::SWAP1,
+		Instruction::SHA3,
+		u256(12),
+		Instruction::DUP3,
+		Instruction::SWAP1,
+		Instruction::MSTORE,
+		Instruction::DUP1
+	});
+}
+
+BOOST_AUTO_TEST_CASE(cse_sha3_twice_same_content_dynamic_store_in_between)
+{
+	// sha3 twice from different dynamic location but with same content,
+	// dynamic mstore in between, which forces us to re-calculate the sha3
+	AssemblyItems input{
+		u256(0x80),
+		Instruction::DUP2,
+		Instruction::DUP2,
+		Instruction::MSTORE, // m[128] = DUP1
+		u256(0x20),
+		Instruction::DUP1,
+		Instruction::DUP3,
+		Instruction::SHA3, // sha3(m[128..(128+32)])
+		u256(12),
+		Instruction::DUP5,
+		Instruction::DUP2,
+		Instruction::MSTORE, // m[12] = DUP1
+		Instruction::DUP12,
+		Instruction::DUP14,
+		Instruction::MSTORE, // destroys memory knowledge
+		Instruction::SWAP2,
+		Instruction::SWAP1,
+		Instruction::SWAP2,
+		Instruction::SHA3 // sha3(m[12..(12+32)])
+	};
+	checkCSE(input, input);
+}
+
+BOOST_AUTO_TEST_CASE(cse_sha3_twice_same_content_noninterfering_store_in_between)
+{
+	// sha3 twice from different dynamic location but with same content,
+	// dynamic mstore in between, but does not force us to re-calculate the sha3
+	AssemblyItems input{
+		u256(0x80),
+		Instruction::DUP2,
+		Instruction::DUP2,
+		Instruction::MSTORE, // m[128] = DUP1
+		u256(0x20),
+		Instruction::DUP1,
+		Instruction::DUP3,
+		Instruction::SHA3, // sha3(m[128..(128+32)])
+		u256(12),
+		Instruction::DUP5,
+		Instruction::DUP2,
+		Instruction::MSTORE, // m[12] = DUP1
+		Instruction::DUP12,
+		u256(12 + 32),
+		Instruction::MSTORE, // does not destoy memory knowledge
+		Instruction::DUP13,
+		u256(128 - 32),
+		Instruction::MSTORE, // does not destoy memory knowledge
+		u256(0x20),
+		u256(12),
+		Instruction::SHA3 // sha3(m[12..(12+32)])
+	};
+	// if this changes too often, only count the number of SHA3 and MSTORE instructions
+	AssemblyItems output = getCSE(input);
+	BOOST_CHECK_EQUAL(4, count(output.begin(), output.end(), AssemblyItem(Instruction::MSTORE)));
+	BOOST_CHECK_EQUAL(1, count(output.begin(), output.end(), AssemblyItem(Instruction::SHA3)));
+}
+
+BOOST_AUTO_TEST_CASE(control_flow_graph_remove_unused)
+{
+	// remove parts of the code that are unused
+	AssemblyItems input{
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMP,
+		u256(7),
+		AssemblyItem(Tag, 1),
+	};
+	checkCFG(input, {});
+}
+
+BOOST_AUTO_TEST_CASE(control_flow_graph_remove_unused_loop)
+{
+	AssemblyItems input{
+		AssemblyItem(PushTag, 3),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 1),
+		u256(7),
+		AssemblyItem(PushTag, 2),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		u256(8),
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 3),
+		u256(11)
+	};
+	checkCFG(input, {u256(11)});
+}
+
+BOOST_AUTO_TEST_CASE(control_flow_graph_reconnect_single_jump_source)
+{
+	// move code that has only one unconditional jump source
+	AssemblyItems input{
+		u256(1),
+		AssemblyItem(PushTag, 1),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		u256(2),
+		AssemblyItem(PushTag, 3),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 1),
+		u256(3),
+		AssemblyItem(PushTag, 2),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 3),
+		u256(4),
+	};
+	checkCFG(input, {u256(1), u256(3), u256(2), u256(4)});
+}
+
+BOOST_AUTO_TEST_CASE(control_flow_graph_do_not_remove_returned_to)
+{
+	// do not remove parts that are "returned to"
+	AssemblyItems input{
+		AssemblyItem(PushTag, 1),
+		AssemblyItem(PushTag, 2),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		Instruction::JUMP,
+		AssemblyItem(Tag, 1),
+		u256(2)
+	};
+	checkCFG(input, {u256(2)});
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}
+} // end namespaces
+
+#endif