diff --git a/libevmcore/Assembly.cpp b/libevmcore/Assembly.cpp
index 9039eaf85..c051bda30 100644
--- a/libevmcore/Assembly.cpp
+++ b/libevmcore/Assembly.cpp
@@ -231,6 +231,12 @@ inline bool matches(AssemblyItemsConstRef _a, AssemblyItemsConstRef _b)
 	return true;
 }
 
+inline bool popCountIncreased(AssemblyItemsConstRef _pre, AssemblyItems const& _post)
+{
+	auto isPop = [](AssemblyItem const& _item) -> bool { return _item.match(AssemblyItem(Instruction::POP)); };
+	return count_if(begin(_post), end(_post), isPop) > count_if(begin(_pre), end(_pre), isPop);
+}
+
 struct OptimiserChannel: public LogChannel { static const char* name() { return "OPT"; } static const int verbosity = 12; };
 #define copt dev::LogOutputStream<OptimiserChannel, true>()
 
@@ -275,8 +281,23 @@ Assembly& Assembly::optimise(bool _enable)
 		rules.push_back({ { Push, Push, i.first }, [&](AssemblyItemsConstRef m) -> AssemblyItems { return { i.second(m[1].data(), m[0].data()) }; } });
 		rules.push_back({ { Push, i.first, Push, i.first }, [&](AssemblyItemsConstRef m) -> AssemblyItems { return { i.second(m[2].data(), m[0].data()), i.first }; } });
 	}
+	// jump to next instruction
 	rules.push_back({ { PushTag, Instruction::JUMP, Tag }, [&](AssemblyItemsConstRef m) -> AssemblyItems { if (m[0].m_data == m[2].m_data) return {m[2]}; else return m.toVector(); }});
 
+	// pop optimization, do not compute values that are popped again anyway
+	rules.push_back({ { AssemblyItem(UndefinedItem), Instruction::POP }, [](AssemblyItemsConstRef m) -> AssemblyItems
+					  {
+						  if (m[0].type() != Operation)
+							return m.toVector();
+						  Instruction instr = Instruction(byte(m[0].data()));
+						  if (Instruction::DUP1 <= instr && instr <= Instruction::DUP16)
+							return {};
+						  InstructionInfo info = instructionInfo(instr);
+						  if (info.sideEffects || info.additional != 0 || info.ret != 1)
+							  return m.toVector();
+						  return AssemblyItems(info.args, Instruction::POP);
+					  } });
+
 	copt << *this;
 
 	unsigned total = 0;
@@ -294,10 +315,10 @@ Assembly& Assembly::optimise(bool _enable)
 			for (auto const& r: rules)
 			{
 				auto vr = AssemblyItemsConstRef(&m_items).cropped(i, r.first.size());
-				if (matches(&r.first, vr))
+				if (matches(vr, &r.first))
 				{
 					auto rw = r.second(vr);
-					if (rw.size() < vr.size())
+					if (rw.size() < vr.size() || (rw.size() == vr.size() && popCountIncreased(vr, rw)))
 					{
 						copt << vr << "matches" << AssemblyItemsConstRef(&r.first) << "becomes...";
 						for (unsigned j = 0; j < vr.size(); ++j)
diff --git a/libevmcore/Instruction.cpp b/libevmcore/Instruction.cpp
index a55cc2242..08c7d87a6 100644
--- a/libevmcore/Instruction.cpp
+++ b/libevmcore/Instruction.cpp
@@ -162,136 +162,136 @@ const std::map<std::string, Instruction> dev::eth::c_instructions =
 };
 
 static const std::map<Instruction, InstructionInfo> c_instructionInfo =
-{ //												Add, Args, Ret
-	{ Instruction::STOP,		{ "STOP",			0, 0, 0 } },
-	{ Instruction::ADD,			{ "ADD",			0, 2, 1 } },
-	{ Instruction::SUB,			{ "SUB",			0, 2, 1 } },
-	{ Instruction::MUL,			{ "MUL",			0, 2, 1 } },
-	{ Instruction::DIV,			{ "DIV",			0, 2, 1 } },
-	{ Instruction::SDIV,		{ "SDIV",			0, 2, 1 } },
-	{ Instruction::MOD,			{ "MOD",			0, 2, 1 } },
-	{ Instruction::SMOD,		{ "SMOD",			0, 2, 1 } },
-	{ Instruction::EXP,			{ "EXP",			0, 2, 1 } },
-	{ Instruction::NOT,		{ "BNOT",			0, 1, 1 } },
-	{ Instruction::LT,			{ "LT",				0, 2, 1 } },
-	{ Instruction::GT,			{ "GT",				0, 2, 1 } },
-	{ Instruction::SLT,			{ "SLT",			0, 2, 1 } },
-	{ Instruction::SGT,			{ "SGT",			0, 2, 1 } },
-	{ Instruction::EQ,			{ "EQ",				0, 2, 1 } },
-	{ Instruction::ISZERO,			{ "NOT",			0, 1, 1 } },
-	{ Instruction::AND,			{ "AND",			0, 2, 1 } },
-	{ Instruction::OR,			{ "OR",				0, 2, 1 } },
-	{ Instruction::XOR,			{ "XOR",			0, 2, 1 } },
-	{ Instruction::BYTE,		{ "BYTE",			0, 2, 1 } },
-	{ Instruction::ADDMOD,		{ "ADDMOD",			0, 3, 1 } },
-	{ Instruction::MULMOD,		{ "MULMOD",			0, 3, 1 } },
-	{ Instruction::SIGNEXTEND,	{ "SIGNEXTEND",		0, 2, 1 } },
-	{ Instruction::SHA3,		{ "SHA3",			0, 2, 1 } },
-	{ Instruction::ADDRESS,		{ "ADDRESS",		0, 0, 1 } },
-	{ Instruction::BALANCE,		{ "BALANCE",		0, 1, 1 } },
-	{ Instruction::ORIGIN,		{ "ORIGIN",			0, 0, 1 } },
-	{ Instruction::CALLER,		{ "CALLER",			0, 0, 1 } },
-	{ Instruction::CALLVALUE,	{ "CALLVALUE",		0, 0, 1 } },
-	{ Instruction::CALLDATALOAD,{ "CALLDATALOAD",	0, 1, 1 } },
-	{ Instruction::CALLDATASIZE,{ "CALLDATASIZE",	0, 0, 1 } },
-	{ Instruction::CALLDATACOPY,{ "CALLDATACOPY",	0, 3, 0 } },
-	{ Instruction::CODESIZE,	{ "CODESIZE",		0, 0, 1 } },
-	{ Instruction::CODECOPY,	{ "CODECOPY",		0, 3, 0 } },
-	{ Instruction::GASPRICE,	{ "GASPRICE",		0, 0, 1 } },
-	{ Instruction::EXTCODESIZE,	{ "EXTCODESIZE",	0, 1, 1 } },
-	{ Instruction::EXTCODECOPY,	{ "EXTCODECOPY",	0, 4, 0 } },
-	{ Instruction::PREVHASH,	{ "PREVHASH",		0, 0, 1 } },
-	{ Instruction::COINBASE,	{ "COINBASE",		0, 0, 1 } },
-	{ Instruction::TIMESTAMP,	{ "TIMESTAMP",		0, 0, 1 } },
-	{ Instruction::NUMBER,		{ "NUMBER",			0, 0, 1 } },
-	{ Instruction::DIFFICULTY,	{ "DIFFICULTY",		0, 0, 1 } },
-	{ Instruction::GASLIMIT,	{ "GASLIMIT",		0, 0, 1 } },
-	{ Instruction::POP,			{ "POP",			0, 1, 0 } },
-	{ Instruction::MLOAD,		{ "MLOAD",			0, 1, 1 } },
-	{ Instruction::MSTORE,		{ "MSTORE",			0, 2, 0 } },
-	{ Instruction::MSTORE8,		{ "MSTORE8",		0, 2, 0 } },
-	{ Instruction::SLOAD,		{ "SLOAD",			0, 1, 1 } },
-	{ Instruction::SSTORE,		{ "SSTORE",			0, 2, 0 } },
-	{ Instruction::JUMP,		{ "JUMP",			0, 1, 0 } },
-	{ Instruction::JUMPI,		{ "JUMPI",			0, 2, 0 } },
-	{ Instruction::PC,			{ "PC",				0, 0, 1 } },
-	{ Instruction::MSIZE,		{ "MSIZE",			0, 0, 1 } },
-	{ Instruction::GAS,			{ "GAS",			0, 0, 1 } },
-	{ Instruction::JUMPDEST,	{ "JUMPDEST",		0, 1, 0 } },
-	{ Instruction::PUSH1,		{ "PUSH1",			1, 0, 1 } },
-	{ Instruction::PUSH2,		{ "PUSH2",			2, 0, 1 } },
-	{ Instruction::PUSH3,		{ "PUSH3",			3, 0, 1 } },
-	{ Instruction::PUSH4,		{ "PUSH4",			4, 0, 1 } },
-	{ Instruction::PUSH5,		{ "PUSH5",			5, 0, 1 } },
-	{ Instruction::PUSH6,		{ "PUSH6",			6, 0, 1 } },
-	{ Instruction::PUSH7,		{ "PUSH7",			7, 0, 1 } },
-	{ Instruction::PUSH8,		{ "PUSH8",			8, 0, 1 } },
-	{ Instruction::PUSH9,		{ "PUSH9",			9, 0, 1 } },
-	{ Instruction::PUSH10,		{ "PUSH10",			10, 0, 1 } },
-	{ Instruction::PUSH11,		{ "PUSH11",			11, 0, 1 } },
-	{ Instruction::PUSH12,		{ "PUSH12",			12, 0, 1 } },
-	{ Instruction::PUSH13,		{ "PUSH13",			13, 0, 1 } },
-	{ Instruction::PUSH14,		{ "PUSH14",			14, 0, 1 } },
-	{ Instruction::PUSH15,		{ "PUSH15",			15, 0, 1 } },
-	{ Instruction::PUSH16,		{ "PUSH16",			16, 0, 1 } },
-	{ Instruction::PUSH17,		{ "PUSH17",			17, 0, 1 } },
-	{ Instruction::PUSH18,		{ "PUSH18",			18, 0, 1 } },
-	{ Instruction::PUSH19,		{ "PUSH19",			19, 0, 1 } },
-	{ Instruction::PUSH20,		{ "PUSH20",			20, 0, 1 } },
-	{ Instruction::PUSH21,		{ "PUSH21",			21, 0, 1 } },
-	{ Instruction::PUSH22,		{ "PUSH22",			22, 0, 1 } },
-	{ Instruction::PUSH23,		{ "PUSH23",			23, 0, 1 } },
-	{ Instruction::PUSH24,		{ "PUSH24",			24, 0, 1 } },
-	{ Instruction::PUSH25,		{ "PUSH25",			25, 0, 1 } },
-	{ Instruction::PUSH26,		{ "PUSH26",			26, 0, 1 } },
-	{ Instruction::PUSH27,		{ "PUSH27",			27, 0, 1 } },
-	{ Instruction::PUSH28,		{ "PUSH28",			28, 0, 1 } },
-	{ Instruction::PUSH29,		{ "PUSH29",			29, 0, 1 } },
-	{ Instruction::PUSH30,		{ "PUSH30",			30, 0, 1 } },
-	{ Instruction::PUSH31,		{ "PUSH31",			31, 0, 1 } },
-	{ Instruction::PUSH32,		{ "PUSH32",			32, 0, 1 } },
-	{ Instruction::DUP1,		{ "DUP1",			0, 1, 2 } },
-	{ Instruction::DUP2,		{ "DUP2",			0, 2, 3 } },
-	{ Instruction::DUP3,		{ "DUP3",			0, 3, 4 } },
-	{ Instruction::DUP4,		{ "DUP4",			0, 4, 5 } },
-	{ Instruction::DUP5,		{ "DUP5",			0, 5, 6 } },
-	{ Instruction::DUP6,		{ "DUP6",			0, 6, 7 } },
-	{ Instruction::DUP7,		{ "DUP7",			0, 7, 8 } },
-	{ Instruction::DUP8,		{ "DUP8",			0, 8, 9 } },
-	{ Instruction::DUP9,		{ "DUP9",			0, 9, 10 } },
-	{ Instruction::DUP10,		{ "DUP10",			0, 10, 11 } },
-	{ Instruction::DUP11,		{ "DUP11",			0, 11, 12 } },
-	{ Instruction::DUP12,		{ "DUP12",			0, 12, 13 } },
-	{ Instruction::DUP13,		{ "DUP13",			0, 13, 14 } },
-	{ Instruction::DUP14,		{ "DUP14",			0, 14, 15 } },
-	{ Instruction::DUP15,		{ "DUP15",			0, 15, 16 } },
-	{ Instruction::DUP16,		{ "DUP16",			0, 16, 17 } },
-	{ Instruction::SWAP1,		{ "SWAP1",			0, 2, 2 } },
-	{ Instruction::SWAP2,		{ "SWAP2",			0, 3, 3 } },
-	{ Instruction::SWAP3,		{ "SWAP3",			0, 4, 4 } },
-	{ Instruction::SWAP4,		{ "SWAP4",			0, 5, 5 } },
-	{ Instruction::SWAP5,		{ "SWAP5",			0, 6, 6 } },
-	{ Instruction::SWAP6,		{ "SWAP6",			0, 7, 7 } },
-	{ Instruction::SWAP7,		{ "SWAP7",			0, 8, 8 } },
-	{ Instruction::SWAP8,		{ "SWAP8",			0, 9, 9 } },
-	{ Instruction::SWAP9,		{ "SWAP9",			0, 10, 10 } },
-	{ Instruction::SWAP10,		{ "SWAP10",			0, 11, 11 } },
-	{ Instruction::SWAP11,		{ "SWAP11",			0, 12, 12 } },
-	{ Instruction::SWAP12,		{ "SWAP12",			0, 13, 13 } },
-	{ Instruction::SWAP13,		{ "SWAP13",			0, 14, 14 } },
-	{ Instruction::SWAP14,		{ "SWAP14",			0, 15, 15 } },
-	{ Instruction::SWAP15,		{ "SWAP15",			0, 16, 16 } },
-	{ Instruction::SWAP16,		{ "SWAP16",			0, 17, 17 } },
-	{ Instruction::LOG0,		{ "LOG0",			0, 1, 0 } },
-	{ Instruction::LOG1,		{ "LOG1",			0, 2, 0 } },
-	{ Instruction::LOG2,		{ "LOG2",			0, 3, 0 } },
-	{ Instruction::LOG3,		{ "LOG3",			0, 4, 0 } },
-	{ Instruction::LOG4,		{ "LOG4",			0, 5, 0 } },
-	{ Instruction::CREATE,		{ "CREATE",			0, 3, 1 } },
-	{ Instruction::CALL,		{ "CALL",			0, 7, 1 } },
-	{ Instruction::CALLCODE,	{ "CALLCODE",		0, 7, 1 } },
-	{ Instruction::RETURN,		{ "RETURN",			0, 2, 0 } },
-	{ Instruction::SUICIDE,		{ "SUICIDE",		0, 1, 0} }
+{ //												Add, Args, Ret, SideEffects
+	{ Instruction::STOP,		{ "STOP",			0, 0, 0, true } },
+	{ Instruction::ADD,			{ "ADD",			0, 2, 1, false } },
+	{ Instruction::SUB,			{ "SUB",			0, 2, 1, false } },
+	{ Instruction::MUL,			{ "MUL",			0, 2, 1, false } },
+	{ Instruction::DIV,			{ "DIV",			0, 2, 1, false } },
+	{ Instruction::SDIV,		{ "SDIV",			0, 2, 1, false } },
+	{ Instruction::MOD,			{ "MOD",			0, 2, 1, false } },
+	{ Instruction::SMOD,		{ "SMOD",			0, 2, 1, false } },
+	{ Instruction::EXP,			{ "EXP",			0, 2, 1, false } },
+	{ Instruction::NOT,			{ "BNOT",			0, 1, 1, false } },
+	{ Instruction::LT,			{ "LT",				0, 2, 1, false } },
+	{ Instruction::GT,			{ "GT",				0, 2, 1, false } },
+	{ Instruction::SLT,			{ "SLT",			0, 2, 1, false } },
+	{ Instruction::SGT,			{ "SGT",			0, 2, 1, false } },
+	{ Instruction::EQ,			{ "EQ",				0, 2, 1, false } },
+	{ Instruction::ISZERO,		{ "NOT",			0, 1, 1, false } },
+	{ Instruction::AND,			{ "AND",			0, 2, 1, false } },
+	{ Instruction::OR,			{ "OR",				0, 2, 1, false } },
+	{ Instruction::XOR,			{ "XOR",			0, 2, 1, false } },
+	{ Instruction::BYTE,		{ "BYTE",			0, 2, 1, false } },
+	{ Instruction::ADDMOD,		{ "ADDMOD",			0, 3, 1, false } },
+	{ Instruction::MULMOD,		{ "MULMOD",			0, 3, 1, false } },
+	{ Instruction::SIGNEXTEND,	{ "SIGNEXTEND",		0, 2, 1, false } },
+	{ Instruction::SHA3,		{ "SHA3",			0, 2, 1, false } },
+	{ Instruction::ADDRESS,		{ "ADDRESS",		0, 0, 1, false } },
+	{ Instruction::BALANCE,		{ "BALANCE",		0, 1, 1, false } },
+	{ Instruction::ORIGIN,		{ "ORIGIN",			0, 0, 1, false } },
+	{ Instruction::CALLER,		{ "CALLER",			0, 0, 1, false } },
+	{ Instruction::CALLVALUE,	{ "CALLVALUE",		0, 0, 1, false } },
+	{ Instruction::CALLDATALOAD,{ "CALLDATALOAD",	0, 1, 1, false } },
+	{ Instruction::CALLDATASIZE,{ "CALLDATASIZE",	0, 0, 1, false } },
+	{ Instruction::CALLDATACOPY,{ "CALLDATACOPY",	0, 3, 0, true } },
+	{ Instruction::CODESIZE,	{ "CODESIZE",		0, 0, 1, false } },
+	{ Instruction::CODECOPY,	{ "CODECOPY",		0, 3, 0, true } },
+	{ Instruction::GASPRICE,	{ "GASPRICE",		0, 0, 1, false } },
+	{ Instruction::EXTCODESIZE,	{ "EXTCODESIZE",	0, 1, 1, false } },
+	{ Instruction::EXTCODECOPY,	{ "EXTCODECOPY",	0, 4, 0, true } },
+	{ Instruction::PREVHASH,	{ "PREVHASH",		0, 0, 1, false } },
+	{ Instruction::COINBASE,	{ "COINBASE",		0, 0, 1, false } },
+	{ Instruction::TIMESTAMP,	{ "TIMESTAMP",		0, 0, 1, false } },
+	{ Instruction::NUMBER,		{ "NUMBER",			0, 0, 1, false } },
+	{ Instruction::DIFFICULTY,	{ "DIFFICULTY",		0, 0, 1, false } },
+	{ Instruction::GASLIMIT,	{ "GASLIMIT",		0, 0, 1, false } },
+	{ Instruction::POP,			{ "POP",			0, 1, 0, false } },
+	{ Instruction::MLOAD,		{ "MLOAD",			0, 1, 1, false } },
+	{ Instruction::MSTORE,		{ "MSTORE",			0, 2, 0, true } },
+	{ Instruction::MSTORE8,		{ "MSTORE8",		0, 2, 0, true } },
+	{ Instruction::SLOAD,		{ "SLOAD",			0, 1, 1, false } },
+	{ Instruction::SSTORE,		{ "SSTORE",			0, 2, 0, true } },
+	{ Instruction::JUMP,		{ "JUMP",			0, 1, 0, true } },
+	{ Instruction::JUMPI,		{ "JUMPI",			0, 2, 0, true } },
+	{ Instruction::PC,			{ "PC",				0, 0, 1, false } },
+	{ Instruction::MSIZE,		{ "MSIZE",			0, 0, 1, false } },
+	{ Instruction::GAS,			{ "GAS",			0, 0, 1, false } },
+	{ Instruction::JUMPDEST,	{ "JUMPDEST",		0, 1, 0, true } },
+	{ Instruction::PUSH1,		{ "PUSH1",			1, 0, 1, false } },
+	{ Instruction::PUSH2,		{ "PUSH2",			2, 0, 1, false } },
+	{ Instruction::PUSH3,		{ "PUSH3",			3, 0, 1, false } },
+	{ Instruction::PUSH4,		{ "PUSH4",			4, 0, 1, false } },
+	{ Instruction::PUSH5,		{ "PUSH5",			5, 0, 1, false } },
+	{ Instruction::PUSH6,		{ "PUSH6",			6, 0, 1, false } },
+	{ Instruction::PUSH7,		{ "PUSH7",			7, 0, 1, false } },
+	{ Instruction::PUSH8,		{ "PUSH8",			8, 0, 1, false } },
+	{ Instruction::PUSH9,		{ "PUSH9",			9, 0, 1, false } },
+	{ Instruction::PUSH10,		{ "PUSH10",			10, 0, 1, false } },
+	{ Instruction::PUSH11,		{ "PUSH11",			11, 0, 1, false } },
+	{ Instruction::PUSH12,		{ "PUSH12",			12, 0, 1, false } },
+	{ Instruction::PUSH13,		{ "PUSH13",			13, 0, 1, false } },
+	{ Instruction::PUSH14,		{ "PUSH14",			14, 0, 1, false } },
+	{ Instruction::PUSH15,		{ "PUSH15",			15, 0, 1, false } },
+	{ Instruction::PUSH16,		{ "PUSH16",			16, 0, 1, false } },
+	{ Instruction::PUSH17,		{ "PUSH17",			17, 0, 1, false } },
+	{ Instruction::PUSH18,		{ "PUSH18",			18, 0, 1, false } },
+	{ Instruction::PUSH19,		{ "PUSH19",			19, 0, 1, false } },
+	{ Instruction::PUSH20,		{ "PUSH20",			20, 0, 1, false } },
+	{ Instruction::PUSH21,		{ "PUSH21",			21, 0, 1, false } },
+	{ Instruction::PUSH22,		{ "PUSH22",			22, 0, 1, false } },
+	{ Instruction::PUSH23,		{ "PUSH23",			23, 0, 1, false } },
+	{ Instruction::PUSH24,		{ "PUSH24",			24, 0, 1, false } },
+	{ Instruction::PUSH25,		{ "PUSH25",			25, 0, 1, false } },
+	{ Instruction::PUSH26,		{ "PUSH26",			26, 0, 1, false } },
+	{ Instruction::PUSH27,		{ "PUSH27",			27, 0, 1, false } },
+	{ Instruction::PUSH28,		{ "PUSH28",			28, 0, 1, false } },
+	{ Instruction::PUSH29,		{ "PUSH29",			29, 0, 1, false } },
+	{ Instruction::PUSH30,		{ "PUSH30",			30, 0, 1, false } },
+	{ Instruction::PUSH31,		{ "PUSH31",			31, 0, 1, false } },
+	{ Instruction::PUSH32,		{ "PUSH32",			32, 0, 1, false } },
+	{ Instruction::DUP1,		{ "DUP1",			0, 1, 2, false } },
+	{ Instruction::DUP2,		{ "DUP2",			0, 2, 3, false } },
+	{ Instruction::DUP3,		{ "DUP3",			0, 3, 4, false } },
+	{ Instruction::DUP4,		{ "DUP4",			0, 4, 5, false } },
+	{ Instruction::DUP5,		{ "DUP5",			0, 5, 6, false } },
+	{ Instruction::DUP6,		{ "DUP6",			0, 6, 7, false } },
+	{ Instruction::DUP7,		{ "DUP7",			0, 7, 8, false } },
+	{ Instruction::DUP8,		{ "DUP8",			0, 8, 9, false } },
+	{ Instruction::DUP9,		{ "DUP9",			0, 9, 10, false } },
+	{ Instruction::DUP10,		{ "DUP10",			0, 10, 11, false } },
+	{ Instruction::DUP11,		{ "DUP11",			0, 11, 12, false } },
+	{ Instruction::DUP12,		{ "DUP12",			0, 12, 13, false } },
+	{ Instruction::DUP13,		{ "DUP13",			0, 13, 14, false } },
+	{ Instruction::DUP14,		{ "DUP14",			0, 14, 15, false } },
+	{ Instruction::DUP15,		{ "DUP15",			0, 15, 16, false } },
+	{ Instruction::DUP16,		{ "DUP16",			0, 16, 17, false } },
+	{ Instruction::SWAP1,		{ "SWAP1",			0, 2, 2, false } },
+	{ Instruction::SWAP2,		{ "SWAP2",			0, 3, 3, false } },
+	{ Instruction::SWAP3,		{ "SWAP3",			0, 4, 4, false } },
+	{ Instruction::SWAP4,		{ "SWAP4",			0, 5, 5, false } },
+	{ Instruction::SWAP5,		{ "SWAP5",			0, 6, 6, false } },
+	{ Instruction::SWAP6,		{ "SWAP6",			0, 7, 7, false } },
+	{ Instruction::SWAP7,		{ "SWAP7",			0, 8, 8, false } },
+	{ Instruction::SWAP8,		{ "SWAP8",			0, 9, 9, false } },
+	{ Instruction::SWAP9,		{ "SWAP9",			0, 10, 10, false } },
+	{ Instruction::SWAP10,		{ "SWAP10",			0, 11, 11, false } },
+	{ Instruction::SWAP11,		{ "SWAP11",			0, 12, 12, false } },
+	{ Instruction::SWAP12,		{ "SWAP12",			0, 13, 13, false } },
+	{ Instruction::SWAP13,		{ "SWAP13",			0, 14, 14, false } },
+	{ Instruction::SWAP14,		{ "SWAP14",			0, 15, 15, false } },
+	{ Instruction::SWAP15,		{ "SWAP15",			0, 16, 16, false } },
+	{ Instruction::SWAP16,		{ "SWAP16",			0, 17, 17, false } },
+	{ Instruction::LOG0,		{ "LOG0",			0, 1, 0, true } },
+	{ Instruction::LOG1,		{ "LOG1",			0, 2, 0, true } },
+	{ Instruction::LOG2,		{ "LOG2",			0, 3, 0, true } },
+	{ Instruction::LOG3,		{ "LOG3",			0, 4, 0, true } },
+	{ Instruction::LOG4,		{ "LOG4",			0, 5, 0, true } },
+	{ Instruction::CREATE,		{ "CREATE",			0, 3, 1, true } },
+	{ Instruction::CALL,		{ "CALL",			0, 7, 1, true } },
+	{ Instruction::CALLCODE,	{ "CALLCODE",		0, 7, 1, true } },
+	{ Instruction::RETURN,		{ "RETURN",			0, 2, 0, true } },
+	{ Instruction::SUICIDE,		{ "SUICIDE",		0, 1, 0, true } }
 };
 
 string dev::eth::disassemble(bytes const& _mem)
diff --git a/libevmcore/Instruction.h b/libevmcore/Instruction.h
index 0892c50dc..eb85c0610 100644
--- a/libevmcore/Instruction.h
+++ b/libevmcore/Instruction.h
@@ -204,6 +204,7 @@ struct InstructionInfo
 	int additional;		///< Additional items required in memory for this instructions (only for PUSH).
 	int args;			///< Number of items required on the stack for this instruction (and, for the purposes of ret, the number taken from the stack).
 	int ret;			///< Number of items placed (back) on the stack by this instruction, assuming args items were removed.
+	bool sideEffects;	///< false if the only effect on the execution environment (apart from gas usage) is a change to a topmost segment of the stack
 };
 
 /// Information on all the instructions.