AArch64 division no longer "traps"

1 files changed, 85 insertions, 36 deletions

diff --git a/aarch64/ConstpropOpproof.v b/aarch64/ConstpropOpproof.v
index deab7cd4..c777062c 100644
--- a/aarch64/ConstpropOpproof.v
+++ b/aarch64/ConstpropOpproof.v
@@ -335,40 +335,63 @@ Qed.
 
 Lemma make_divimm_correct:
   forall n r1 r2 v,
-  Val.divs e#r1 e#r2 = Some v ->
+  Val.maketotal (Val.divs e#r1 e#r2) = v ->
   e#r2 = Vint n ->
   let (op, args) := make_divimm n r1 r2 in
   exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.
 Proof.
   intros; unfold make_divimm.
-  predSpec Int.eq Int.eq_spec n Int.one; intros. subst. rewrite H0 in H.
-  destruct (e#r1) eqn:?;
-    try (rewrite Val.divs_one in H; exists (Vint i); split; simpl; try rewrite Heqv0; auto);
-    inv H; auto.
-  destruct (Int.is_power2 n) eqn:?.
-  destruct (Int.ltu i (Int.repr 31)) eqn:?.
-  exists v; split; auto. simpl. eapply Val.divs_pow2; eauto. congruence.
-  exists v; auto.
-  exists v; auto.
+  predSpec Int.eq Int.eq_spec n Int.one; intros; subst; rewrite H0.
+  { destruct (e # r1) eqn:Er1.
+    all: try (cbn; exists (e # r1); split; auto; fail).
+    rewrite Val.divs_one.
+    cbn.
+    rewrite Er1.
+    exists (Vint i); split; auto.
+ }
+ destruct (Int.is_power2 n) eqn:Power2.
+ {
+    destruct (Int.ltu i (Int.repr 31)) eqn:iLT31.
+    {
+      cbn.
+      exists (Val.maketotal (Val.shrx e # r1 (Vint i))); split; auto.
+      destruct (Val.divs e # r1 (Vint n)) eqn:DIVS; cbn; auto.
+      rewrite Val.divs_pow2 with (y:=v) (n:=n).
+      cbn.
+      all: auto.
+    }
+    exists (Val.maketotal (Val.divs e # r1 (Vint n))); split; cbn; auto; congruence.
+ }
+ exists (Val.maketotal (Val.divs e # r1 (Vint n))); split; cbn; auto; congruence.
 Qed.
 
+
 Lemma make_divuimm_correct:
   forall n r1 r2 v,
-  Val.divu e#r1 e#r2 = Some v ->
+  Val.maketotal (Val.divu e#r1 e#r2) = v ->
   e#r2 = Vint n ->
   let (op, args) := make_divuimm n r1 r2 in
   exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.
 Proof.
   intros; unfold make_divuimm.
-  predSpec Int.eq Int.eq_spec n Int.one; intros. subst. rewrite H0 in H.
-  destruct (e#r1) eqn:?;
-    try (rewrite Val.divu_one in H; exists (Vint i); split; simpl; try rewrite Heqv0; auto);
-    inv H; auto.
-  destruct (Int.is_power2 n) eqn:?.
-  econstructor; split. simpl; eauto.
-  rewrite mk_amount32_eq by (eapply Int.is_power2_range; eauto).
-  rewrite H0 in H. erewrite Val.divu_pow2 by eauto. auto.
-  exists v; auto.
+  predSpec Int.eq Int.eq_spec n Int.one; intros; subst; rewrite H0.
+  { destruct (e # r1) eqn:Er1.
+    all: try (cbn; exists (e # r1); split; auto; fail).
+    rewrite Val.divu_one.
+    cbn.
+    rewrite Er1.
+    exists (Vint i); split; auto.
+ }
+ destruct (Int.is_power2 n) eqn:Power2.
+ {
+   cbn.
+   rewrite mk_amount32_eq by (eapply Int.is_power2_range; eauto).
+   exists (Val.shru e # r1 (Vint i)); split; auto.
+   destruct (Val.divu e # r1 (Vint n)) eqn:DIVU; cbn; auto.
+   rewrite Val.divu_pow2 with (y:=v) (n:=n).
+   all: auto.
+ }
+ exists (Val.maketotal (Val.divu e # r1 (Vint n))); split; cbn; auto; congruence.
 Qed.
 
 Lemma make_andimm_correct:
@@ -503,34 +526,60 @@ Qed.
 
 Lemma make_divlimm_correct:
   forall n r1 r2 v,
-  Val.divls e#r1 e#r2 = Some v ->
+  Val.maketotal (Val.divls e#r1 e#r2) = v ->
   e#r2 = Vlong n ->
   let (op, args) := make_divlimm n r1 r2 in
   exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.
 Proof.
   intros; unfold make_divlimm.
-  destruct (Int64.is_power2' n) eqn:?. destruct (Int.ltu i (Int.repr 63)) eqn:?.
-  rewrite H0 in H. econstructor; split. simpl; eauto. eapply Val.divls_pow2; eauto. auto.
-  exists v; auto.
-  exists v; auto.
+ destruct (Int64.is_power2' n) eqn:Power2.
+ {
+    destruct (Int.ltu i (Int.repr 63)) eqn:iLT63.
+    {
+      cbn.
+      exists (Val.maketotal (Val.shrxl e # r1 (Vint i))); split; auto.
+      rewrite H0 in H.
+      destruct (Val.divls e # r1 (Vlong n)) eqn:DIVS; cbn in H; auto.
+      {
+        subst v0.
+        rewrite Val.divls_pow2 with (y:=v) (n:=n).
+        cbn.
+        all: auto.
+      }
+      subst. auto.
+    }
+    cbn. subst. rewrite H0.
+    exists (Val.maketotal (Val.divls e # r1 (Vlong n))); split; auto.
+ }
+ cbn. subst. rewrite H0.
+ exists (Val.maketotal (Val.divls e # r1 (Vlong n))); split; auto.
 Qed.
 
+
 Lemma make_divluimm_correct:
   forall n r1 r2 v,
-  Val.divlu e#r1 e#r2 = Some v ->
+  Val.maketotal (Val.divlu e#r1 e#r2) = v ->
   e#r2 = Vlong n ->
   let (op, args) := make_divluimm n r1 r2 in
   exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.
 Proof.
   intros; unfold make_divluimm.
   destruct (Int64.is_power2' n) eqn:?.
+  {
   econstructor; split. simpl; eauto.
-  rewrite mk_amount64_eq by (eapply Int64.is_power2'_range; eauto).
-  rewrite H0 in H. destruct (e#r1); inv H. destruct (Int64.eq n Int64.zero); inv H2.
-  simpl.
-  erewrite Int64.is_power2'_range by eauto.    
-  erewrite Int64.divu_pow2' by eauto.  auto. 
-  exists v; auto.
+  rewrite H0 in H. destruct (e#r1); inv H.
+  all: cbn; auto.
+  {
+    rewrite mk_amount64_eq by (eapply Int64.is_power2'_range; eauto).
+    destruct (Int64.eq n Int64.zero); cbn; auto.
+    erewrite Int64.is_power2'_range by eauto.    
+    erewrite Int64.divu_pow2' by eauto.  auto.
+  }
+  }
+  exists v; split; auto.
+  cbn.
+  rewrite H.
+  reflexivity.
 Qed.
 
 Lemma make_andlimm_correct:
@@ -679,10 +728,10 @@ Proof.
   InvApproxRegs; SimplVM; inv H0. apply make_mulimm_correct; auto.
 - (* divs *)
   assert (e#r2 = Vint n2). clear H0. InvApproxRegs; SimplVM; auto.
-  apply make_divimm_correct; auto.
+  apply make_divimm_correct; auto. congruence.
 - (* divu *)
   assert (e#r2 = Vint n2). clear H0. InvApproxRegs; SimplVM; auto.
-  apply make_divuimm_correct; auto.
+  apply make_divuimm_correct; auto. congruence.
 - (* and 1 *)
   rewrite Val.and_commut in H0. InvApproxRegs; SimplVM; inv H0. apply make_andimm_correct; auto.
 - (* and 2 *)
@@ -745,10 +794,10 @@ Proof.
   InvApproxRegs; SimplVM; inv H0. apply make_mullimm_correct; auto.
 - (* divl *)
   assert (e#r2 = Vlong n2). clear H0. InvApproxRegs; SimplVM; auto.
-  apply make_divlimm_correct; auto.
+  apply make_divlimm_correct; auto. congruence.
 - (* divlu *)
   assert (e#r2 = Vlong n2). clear H0. InvApproxRegs; SimplVM; auto.
-  apply make_divluimm_correct; auto.
+  apply make_divluimm_correct; auto. congruence.
 - (* andl 1 *)
   rewrite Val.andl_commut in H0. InvApproxRegs; SimplVM; inv H0. apply make_andlimm_correct; auto.
 - (* andl 2 *)