When is an integer<->pointer cast actually correct?

Question

The common folklore says that:

• The type system exists for a reason. Integers and pointers are distinct types, casting between them is a malpractice in the m

Answer 1

It could be useful when checking the alignment of types in general so that misaligned memory gets caught with an assert rather than just SIGBUS/SIGSEGV.

E.g.:

#include 
#include 
#include 

int main() {
  void *ptr = malloc(sizeof(__m128));
  assert(!((intptr_t)ptr) % __alignof__(__m128));
  return 0;
}

(In real code I wouldn't just gamble on malloc, but it illustrates the point)