Remark decompose_cmpl_lt_zero:
  forall h l,
  Int64.lt (Int64.ofwords h l) Int64.zero = Int.lt h Int.zero.

Theorem eval_cmpl: forall c le a x b y v, eval_expr ge sp e m le a x -> eval_expr ge sp e m le b y -> Val.cmpl c x y = Some v -> eval_expr ge sp e m le (cmpl c a b) v.