let update_at_label env label p =
if label = Clabels.Here then p
else try
let mem_here = mem_at env Clabels.Here in
let mem_label = find_mem_at env label in
let vma_label = valloc_of_mem mem_label in
let vmb_label = vbits_of_mem mem_label in
let p = D.subst vmb_label (mbits_of_mem mem_here) p in
let p = D.subst vma_label (malloc_of_mem mem_here) p in
p
with Not_found -> p