Local Open Scope pred.
(* Scall *)
Fixpoint alloc_juicy_variables (ge: genv) (rho: env) (jm: juicy_mem) (vl: list (ident*type)) : env * juicy_mem :=
match vl with
| nil => (rho,jm)
| (id,ty)::vars => match JuicyMemOps.juicy_mem_alloc jm 0 (@sizeof ge ty) with
(m1,b1) => alloc_juicy_variables ge (PTree.set id (b1,ty) rho) m1 vars
end
end.
Definition substopt {A} (ret: option ident) (v: val) (P: environ -> A)  : environ -> A :=
match ret with
| Some id => subst id v P
| None => P
end.

Lemma fst_split {T1 T2}: forall vl: list (T1*T2), fst (split vl) = map fst vl.