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.