End EVAL_COMPAT.
(** Compatibility of the evaluation functions with the ``is less defined'' relation over values. *)
Section EVAL_LESSDEF.
Variable F V: Type.
Variable genv: Genv.t F V.
Remark valid_pointer_extends:
forall m1 m2, Mem.extends m1 m2 ->
forall b1 ofs b2 delta,
Some(b1, 0) = Some(b2, delta) ->
Mem.valid_pointer m1 b1 (Ptrofs.unsigned ofs) = true ->
Mem.valid_pointer m2 b2 (Ptrofs.unsigned (Ptrofs.add ofs (Ptrofs.repr delta))) = true.
Remark weak_valid_pointer_extends:
forall m1 m2, Mem.extends m1 m2 ->
forall b1 ofs b2 delta,
Some(b1, 0) = Some(b2, delta) ->
Mem.weak_valid_pointer m1 b1 (Ptrofs.unsigned ofs) = true ->
Mem.weak_valid_pointer m2 b2 (Ptrofs.unsigned (Ptrofs.add ofs (Ptrofs.repr delta))) = true.
Remark weak_valid_pointer_no_overflow_extends:
forall m1 b1 ofs b2 delta,
Some(b1, 0) = Some(b2, delta) ->
Mem.weak_valid_pointer m1 b1 (Ptrofs.unsigned ofs) = true ->
0 <= Ptrofs.unsigned ofs + Ptrofs.unsigned (Ptrofs.repr delta) <= Ptrofs.max_unsigned.
Remark valid_different_pointers_extends:
forall m1 b1 ofs1 b2 ofs2 b1' delta1 b2' delta2,
b1 <> b2 ->
Mem.valid_pointer m1 b1 (Ptrofs.unsigned ofs1) = true ->
Mem.valid_pointer m1 b2 (Ptrofs.unsigned ofs2) = true ->
Some(b1, 0) = Some (b1', delta1) ->
Some(b2, 0) = Some (b2', delta2) ->
b1' <> b2' \/
Ptrofs.unsigned(Ptrofs.add ofs1 (Ptrofs.repr delta1)) <> Ptrofs.unsigned(Ptrofs.add ofs2 (Ptrofs.repr delta2)).

Lemma eval_operation_lessdef:
forall sp op vl1 vl2 v1 m1 m2,
Val.lessdef_list vl1 vl2 ->
Mem.extends m1 m2 ->
eval_operation genv sp op vl1 m1 = Some v1 ->
exists v2, eval_operation genv sp op vl2 m2 = Some v2 /\ Val.lessdef v1 v2.