> If foo is false in your code, then the behavior is completely defined.
That's the point. If foo is false, both versions do the same thing. If foo is true, then it's undefined and it doesn't matter. Therefore, assume foo is false. Remove the branch.
That's the point. If foo is false, both versions do the same thing. If foo is true, then it's undefined and it doesn't matter. Therefore, assume foo is false. Remove the branch.