Comment 27 for bug 1347147

The testcase is violating strict-aliasing rules as you access a struct head
as struct node here:

  if (n->prev == (void *)h)
    h->first = n->next;
  else
    n->prev->next = n->next;

as n->prev points to &heads[0] while h is &heads[2] (an out-of-bound pointer).
So n->prev is a struct head and you access a next field of a struct node of it.

Changing k to 0 makes the testcase pass (now you don't run into the bogus
path).