But that probably isn't the function you want, because that will return -1 if the input is negative. What you want to return is a boolean. And in that case the

But that probably isn't the function you want, because that will return -1 if the input is negative. What you want to return is a boolean. And in that case the code generated is much simpler https://godbolt.org/z/5dq7MnrEx https://godbolt.org/z/5dq7MnrEx