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 return_regs_arg_values:
forall sg ls1 ls2,
tailcall_is_possible sg = true ->
map (fun p => Locmap.getpair p (return_regs ls1 ls2)) (loc_arguments sg)
= map (fun p => Locmap.getpair p ls2) (loc_arguments sg).