(** ** Constructing block classifications *)
Definition bc_nostack (bc: block_classification) : Prop :=
forall b, bc b <> BCstack.
Section NOSTACK.
Variable bc: block_classification.
Hypothesis NOSTACK: bc_nostack bc.

Lemma pmatch_no_stack: forall b ofs p, pmatch bc b ofs p -> pmatch bc b ofs Nonstack.