placement delete function is never called upon exception

The placement delete is used to deallocate the memory when an exception occurs in the placement new. So I ran a test:

class A {
public:
    A(){
        cout << "constructor" << endl;
        throw 1;
    }
};

void* operator new(size_t size, int i){
    cout << "in placement new" << endl;
    return ::operator new(size);
}

void operator delete(void *ptr, int i){
    cout << "in placement delete" << endl;
    ::operator delete(ptr);
}

int main(){
    int o = 9;
    A* a = new(o) A;
}

And the placement delete function was never called, it just simply exited. Why?