gcc/testsuite/gcc.c-torture/execute/pr19687.c

extern void abort (void);

union U
{
  int i, j[4];
};

int main ()
{
  union U t = {};
  int i;

  for (i = 0; i < 4; ++i)
    if (t.j[i] != 0)
      abort ();

  return 0;
}