>If you understand how computers work it is extremely reliable bar none.

On my processor, INT64_MAX + 1 will be INT64_MIN, a negative value. But the compiler is free to turn

  for (int64_t i = 1; i > 0; i++) {
  	f(i);
  }

into an infinite loop. Understanding how the computer works without reading about undefined behavior will make you fall into these kinds of traps.