Memory allocated with alloca gets freed at end of function or at end of scope?

If I have a function like this:

void bla(int size) {
    while(b){
        char tmp[size];
        ......
    }
}

tmp gets freed at each iteration of the while loop, right?

If I write this function:

void bla(int size) {
    while(b){
        char* tmp = alloca(size);
        ......
    }
}

tmp gets freed at end of scope or at end of function?