Recombine x = cmp(...); if (x == 1) ...

      and  x = cmp(...); if (x != 1) ...


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1946 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

2 files changed, 47 insertions, 4 deletions

diff --git a/arm/CombineOp.v b/arm/CombineOp.v
index 8048653..d153b73 100644
--- a/arm/CombineOp.v
+++ b/arm/CombineOp.v
@@ -41,16 +41,30 @@ Function combine_compimm_eq_0 (x: valnum) : option(condition * list valnum) :=
   | _ => None
   end.
 
+Function combine_compimm_ne_1 (x: valnum) : option(condition * list valnum) :=
+  match get x with
+  | Some(Op (Ocmp c) ys) => Some (negate_condition c, ys)
+  | _ => None
+  end.
+
 Function combine_cond (cond: condition) (args: list valnum) : option(condition * list valnum) :=
   match cond, args with
   | Ccompimm Cne n, x::nil =>
-      if Int.eq_dec n Int.zero then combine_compimm_ne_0 x else None
+      if Int.eq_dec n Int.zero then combine_compimm_ne_0 x
+      else if Int.eq_dec n Int.one then combine_compimm_ne_1 x
+      else None
   | Ccompimm Ceq n, x::nil =>
-      if Int.eq_dec n Int.zero then combine_compimm_eq_0 x else None
+      if Int.eq_dec n Int.zero then combine_compimm_eq_0 x
+      else if Int.eq_dec n Int.one then combine_compimm_eq_1 x
+      else None
   | Ccompuimm Cne n, x::nil =>
-      if Int.eq_dec n Int.zero then combine_compimm_ne_0 x else None
+      if Int.eq_dec n Int.zero then combine_compimm_ne_0 x
+      else if Int.eq_dec n Int.one then combine_compimm_ne_1 x
+      else None
   | Ccompuimm Ceq n, x::nil =>
-      if Int.eq_dec n Int.zero then combine_compimm_eq_0 x else None
+      if Int.eq_dec n Int.zero then combine_compimm_eq_0 x
+      else if Int.eq_dec n Int.one then combine_compimm_eq_1 x
+      else None
   | _, _ => None
   end.
 
diff --git a/arm/CombineOpproof.v b/arm/CombineOpproof.v
index 9d297ac..0d2e6dd 100644
--- a/arm/CombineOpproof.v
+++ b/arm/CombineOpproof.v
@@ -58,6 +58,31 @@ Proof.
   destruct (eval_condition c (map valu args) m); simpl; auto. destruct b; auto.
 Qed.
 
+Lemma combine_compimm_eq_1_sound:
+  forall x cond args,
+  combine_compimm_eq_1 get x = Some(cond, args) ->
+  eval_condition cond (map valu args) m = Val.cmp_bool Ceq (valu x) (Vint Int.one) /\
+  eval_condition cond (map valu args) m = Val.cmpu_bool (Mem.valid_pointer m) Ceq (valu x) (Vint Int.one).
+Proof.
+  intros until args. functional induction (combine_compimm_eq_1 get x); intros EQ; inv EQ.
+  (* of cmp *)
+  exploit get_sound; eauto. unfold equation_holds. simpl. intro EQ; inv EQ. 
+  destruct (eval_condition cond (map valu args) m); simpl; auto. destruct b; auto.
+Qed.
+
+Lemma combine_compimm_ne_1_sound:
+  forall x cond args,
+  combine_compimm_ne_1 get x = Some(cond, args) ->
+  eval_condition cond (map valu args) m = Val.cmp_bool Cne (valu x) (Vint Int.one) /\
+  eval_condition cond (map valu args) m = Val.cmpu_bool (Mem.valid_pointer m) Cne (valu x) (Vint Int.one).
+Proof.
+  intros until args. functional induction (combine_compimm_eq_1 get x); intros EQ; inv EQ.
+  (* of cmp *)
+  exploit get_sound; eauto. unfold equation_holds. simpl. intro EQ; inv EQ. 
+  rewrite eval_negate_condition.
+  destruct (eval_condition cond (map valu args) m); simpl; auto. destruct b; auto.
+Qed.
+
 Theorem combine_cond_sound:
   forall cond args cond' args',
   combine_cond get cond args = Some(cond', args') ->
@@ -68,10 +93,14 @@ Proof.
   simpl; eapply combine_compimm_ne_0_sound; eauto.
   (* compimm eq zero *)
   simpl; eapply combine_compimm_eq_0_sound; eauto.
+  (* compimm eq one *)
+  simpl; eapply combine_compimm_eq_1_sound; eauto.
   (* compuimm ne zero *)
   simpl; eapply combine_compimm_ne_0_sound; eauto.
   (* compuimm eq zero *)
   simpl; eapply combine_compimm_eq_0_sound; eauto.
+  (* compuimm eq one *)
+  simpl; eapply combine_compimm_eq_1_sound; eauto.
 Qed.
 
 Theorem combine_addr_sound: