Function find

src/backend/cpu/kernel/regions.hpp:48–51

template<typename T>
static LabelNode<T>* find(LabelNode<T>* x) {
    if (x->getParent() != x) x->setParent(find(x->getParent()));
    return x->getParent();
}

template<typename T>
static void setUnion(LabelNode<T>* x, LabelNode<T>* y) {