Remark eval_builtin_args_trivial:
forall (ge: RTL.genv) (rs: regset) sp m rl,
eval_builtin_args ge (fun r => rs#r) sp m (List.map (@BA reg) rl) rs##rl.

Lemma transl_expr_Eexternal_correct:
forall le id sg al b ef vl v,
Genv.find_symbol ge id = Some b ->
Genv.find_funct_ptr ge b = Some (External ef) ->
ef_sig ef = sg ->
eval_exprlist ge sp e m le al vl ->
transl_exprlist_prop le al vl ->
external_call ef ge vl m E0 v m ->
transl_expr_prop le (Eexternal id sg al) v.