/* { dg-do run } */
/* { dg-options "-O3 -fstrict-aliasing" } */

union U {
  struct A { int : 2; int x : 8; } a;
  struct B { int : 6; int x : 8; } b;
};

int __attribute__((noipa))
foo (union U *p, union U *q)
{
  p->a.x = 1;
  q->b.x = 1;
  return p->a.x;
}

int
main()
{
  union U x;
  if (foo (&x, &x) != x.a.x)
    __builtin_abort ();
  return 0;
}

/* We support arbitrary punning through unions when it happens through
   the union type and thus p == q is valid here.  */