Definition freeable_blocks: list (block * BinInt.Z * BinInt.Z) -> mpred :=
  fold_right (fun (bb: block*BinInt.Z * BinInt.Z) a => 
                        match bb with (b,lo,hi) => 
                                          sepcon (VALspec_range (hi-lo) Share.top (b,lo)) a
                        end)
                    emp.

Lemma VALspec_range_free: forall n b phi1 jm, app_pred (VALspec_range n Share.top (b, 0)) phi1 -> join_sub phi1 (m_phi jm) -> {m' | free (m_dry jm) b 0 n = Some m' }.