Remark val_lessdef_normalize:
forall v v' ty,
Val.has_type v ty -> Val.lessdef v v' ->
Val.lessdef v (Val.load_result (chunk_of_type ty) v').

Lemma add_equations_builtin_arg_lessdef:
forall env (ge: RTL.genv) sp rs ls m arg v,
eval_builtin_arg ge (fun r => rs#r) sp m arg v ->
forall e e' arg',
add_equations_builtin_arg env arg arg' e = Some e' ->
satisf rs ls e' ->
wt_regset env rs ->
exists v', eval_builtin_arg ge ls sp m arg' v' /\ Val.lessdef v v'.