> I declare that this rule does not apply here ...

Clearly the gcc developers disagree. :-)


iwasawa:~ mdickinson$ cat test2.c
int is_positive_zero(double f) {
  return *(long long*)&f == 0;
}
iwasawa:~ mdickinson$ gcc -fstrict-aliasing -O3 -Wall -Wextra -Wstrict-aliasing -c test2.c
test2.c: In function ‘is_positive_zero’:
test2.c:2: warning: dereferencing type-punned pointer will break strict-aliasing rules