Ltac destruct_cjoin phi HH :=
match goal with
|   |- context [@proj1_sig rmap _ ?X] => destruct X as [phi HH]; simpl
|  H: context [@proj1_sig rmap _ ?X] |- _ => destruct X as [phi HH]; simpl in H
end.

Lemma dec_pure: forall r, {exists k, exists pp, r = PURE k pp}+{core r = NO Share.bot bot_unreadable}.