Module spred. Section spred.
Variables x y z : spred.
Local Open Scope pred.

Lemma lseg_lseg_app: forall x y z h1 h2 h tz,
lseg x y h1 ->
lseg y z h2 ->
join h2 h1 h ->
val2loc z = Some tz ->
emp_at tz h ->
lseg x z h.