Method overflowCheckedIntAddFunction

libsolidity/codegen/YulUtilFunctions.cpp:720–762

}

std::string YulUtilFunctions::overflowCheckedIntAddFunction(IntegerType const& _type)
{
	std::string functionName = "checked_add_" + _type.identifier();
	return m_functionCollector.createFunction(functionName, [&]() {
		return
			Whiskers(R"(
			function <functionName>(x, y) -> sum {
				x := <cleanupFunction>(x)
				y := <cleanupFunction>(y)
				sum := add(x, y)
				<?signed>
					<?256bit>
						// overflow, if x >= 0 and sum < y
						// underflow, if x < 0 and sum >= y
						if or(
							and(iszero(slt(x, 0)), slt(sum, y)),
							and(slt(x, 0), iszero(slt(sum, y)))
						) { <panic>() }
					<!256bit>
						if or(
							sgt(sum, <maxValue>),
							slt(sum, <minValue>)
						) { <panic>() }
					</256bit>
				<!signed>
					<?256bit>
						if gt(x, sum) { <panic>() }
					<!256bit>
						if gt(sum, <maxValue>) { <panic>() }
					</256bit>
				</signed>
			}
			)")
			("functionName", functionName)
			("signed", _type.isSigned())
			("maxValue", toCompactHexWithPrefix(u256(_type.maxValue())))
			("minValue", toCompactHexWithPrefix(u256(_type.minValue())))
			("cleanupFunction", cleanupFunction(_type))
			("panic", panicFunction(PanicCode::UnderOverflow))
			("256bit", _type.numBits() == 256)
			.render();
	});
}

std::string YulUtilFunctions::wrappingIntAddFunction(IntegerType const& _type)
{