Term for when you stop code execution early on with an if?

What's the term for when you stop code flow early on with some sort of if statement and a return value?

E.g.:

bool myFunc(){
    if(userNotAllowed){ // <- What is this called?
        return false; // I've heard it given a name before.
    }
    //do lots of stuff
    //etc etc
    return true;
}

It's a sort of simple design pattern of sorts... An example would be look-before-you-leap or it's "Easier to Ask Forgiveness than Permission". But I don't think it has a silly name like that.