An alias bug?

[hjl at lucon dot org (H.J. Lu)]

I got this with egcs-2.91.42 19980627:

# gcc foo.c
# a.out
# gcc -O foo.c
# a.out
zsh: 3823 abort      ./a.out

Is this an alias bug or the code is buggy?

Thanks.


-- 
H.J. Lu (hjl@gnu.org)
---foo.c--
static long
Add (long *C, long *A, long *B, unsigned int N)
{
  long carry = 0;
  unsigned int i;
  for (i = 0; i < N; i+=2)
  {
    long long u = (long long) carry + A [i] + B [i];
    C [i] = (long) u;
#if 1
    u = (long long) (*(((long *)&( u ))+1)) + A [i+1] + B [i+1];
#else
    carry = (*(((long *)&(u))+1));
    u = (long long) carry  + A [i+1] + B [i+1];
#endif
    C [i+1] = (long) u;
    carry = (*(((long *)&(u))+1));
  }

  return carry;
}

main ()
{
  long A [2] = {0};
  long B [2] = {2, 0};

  Add (A, A, B, 2);
  if (A [0] != 2 || A [1] != 0)
    abort ();
  return 0;
}