Definition size_compatible' (n: Z) (p: val) :=
match p with
| Vundef => True
| Vint _ => True
| Vlong _ => True
| Vfloat _ => True
| Vsingle _ => True
| Vptr _ i_ofs => Ptrofs.unsigned i_ofs + n < Ptrofs.modulus
end.

Lemma memory_block_mapsto_: forall sh t p, type_is_by_value t = true -> type_is_volatile t = false -> size_compatible t p -> align_compatible t p -> memory_block sh (sizeof t) p = mapsto_ sh t p.