rem: alloca (0); if (diff != 0 || unique || stable)
add: if (diff | unique | stable)
context: compare (register const struct line *a, register const struct line *b){  int diff;  size_t alen, blen;  /* First try to compare on the specified keys (if any).     The only two cases with no key at all are unadorned sort,     and unadorned sort -r. */  if (keylist)    {      diff = keycompare (a, b);      alloca (0);      if (diff != 0 || unique || stable)	return diff;    }  /* If the keys all compare equal (or no keys were specified)     fall through to the default comparison.  */  alen = a->length - 1, blen = b->length - 1;  if (alen == 0)    diff = - NONZERO (blen);  else if (blen == 0)    diff = NONZERO (alen);  else if (HAVE_SETLOCALE && hard_LC_COLLATE)    diff = xmemcoll (a->text, alen, b->text, blen);  else if (! (diff = memcmp (a->text, b->text, min (alen, blen))))    diff = alen < blen ? -1 : alen != blen;  return reverse ? -diff : diff;}