More realistic treatment of jump tables: show the absence of overflow when accessing the table

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1172 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

2 files changed, 14 insertions, 0 deletions

diff --git a/lib/Coqlib.v b/lib/Coqlib.v
index 7bc4f8b..02fa7ba 100644
--- a/lib/Coqlib.v
+++ b/lib/Coqlib.v
@@ -648,6 +648,13 @@ Proof.
   rewrite list_length_z_cons. omega.
 Qed.
 
+Lemma list_length_z_map:
+  forall (A B: Type) (f: A -> B) (l: list A),
+  list_length_z (map f l) = list_length_z l.
+Proof.
+  induction l. reflexivity. simpl. repeat rewrite list_length_z_cons. congruence.
+Qed. 
+
 (** Extract the n-th element of a list, as [List.nth_error] does,
     but the index [n] is of type [Z]. *)
 
diff --git a/lib/Integers.v b/lib/Integers.v
index c54b6fe..625973a 100644
--- a/lib/Integers.v
+++ b/lib/Integers.v
@@ -871,6 +871,13 @@ Proof.
   apply neg_mul_distr_l. 
 Qed.
 
+Theorem mul_signed:
+  forall x y, mul x y = repr (signed x * signed y).
+Proof.
+  intros; unfold mul. apply eqm_samerepr.
+  apply eqm_mult; apply eqm_sym; apply eqm_signed_unsigned.
+Qed.
+
 (** ** Properties of binary decompositions *)
 
 Lemma Z_shift_add_bin_decomp: