Building a list of types used for the function

Assuming I have a function in the following form,

template<typename T>
int some_call(T t){
  return t;
}

Is is possible to in compile time build a list of typenames and find the largest T used. i.e,

  some_call(int(42));
  some_call(long(42));

I would like to find sizeof(long) since it is largest size used. The reason I am trying to do is I will allocate an array to hold some memory for a calculation I would like to allocate big enough to hold largest type.