Definition bmatch (m: mem) (b: block) (ab: ablock) : Prop :=
  smatch m b ab.(ab_summary) /\
  forall chunk ofs v, Mem.load chunk m b ofs = Some v -> vmatch v (ablock_load chunk ab ofs).

Lemma ablock_load_sound: forall chunk m b ofs v ab, Mem.load chunk m b ofs = Some v -> bmatch m b ab -> vmatch v (ablock_load chunk ab ofs).