_ f(int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k) {
  return (b, a, c, e, g, d, f, k, i, j, h);   ;; optimal code is 4 ops, 8 bytes
  ;; s5 s0 s8 XCHG3  2 9 BLKSWAP  s8 s9 s10 XCHG3  s7 s0 s5 XCHG3
}