Remark type_expect_incr:
  forall e ty1 ty2 e' te, type_expect e ty1 ty2 = OK e' -> S.satisf te e' -> S.satisf te e.

Lemma wt_exec_Ibuiltin: forall env f ef (ge: genv) args res s vargs m t vres m' rs, wt_instr f env (Ibuiltin ef args res s) -> external_call ef ge vargs m t vres m' -> wt_regset env rs -> wt_regset env (regmap_setres res vres rs).