Fine-tuning of the "andimm" case to generate a move rather than an andimm when possible.

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2348 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

2 files changed, 13 insertions, 2 deletions

diff --git a/powerpc/CombineOp.v b/powerpc/CombineOp.v
index b92e045..5cb7630 100644
--- a/powerpc/CombineOp.v
+++ b/powerpc/CombineOp.v
@@ -101,8 +101,12 @@ Function combine_op (op: operation) (args: list valnum) : option(operation * lis
       end
   | Oandimm n, x :: nil =>
       match get x with
-      | Some(Op (Oandimm m) ys) => Some(Oandimm (Int.and m n), ys)
-      | Some(Op (Orolm amount m) ys) => Some(Orolm amount (Int.and m n), ys)
+      | Some(Op (Oandimm m) ys) => 
+          Some(let p := Int.and m n in
+               if Int.eq p m then (Omove, x :: nil) else (Oandimm p, ys))
+      | Some(Op (Orolm amount m) ys) =>
+          Some(let p := Int.and m n in
+               if Int.eq p m then (Omove, x :: nil) else (Orolm amount p, ys))
       | _ => None
       end
   | Oorimm n, x :: nil =>
diff --git a/powerpc/CombineOpproof.v b/powerpc/CombineOpproof.v
index 8f4ae19..0e328df 100644
--- a/powerpc/CombineOpproof.v
+++ b/powerpc/CombineOpproof.v
@@ -147,9 +147,16 @@ Transparent Val.sub.
   destruct v; simpl; auto. repeat rewrite Int.sub_add_opp. rewrite Int.add_assoc.
   rewrite Int.neg_add_distr. decEq. decEq. decEq. apply Int.add_commut.
 (* andimm - andimm *)
+  generalize (Int.eq_spec p m0); rewrite H7; intros. 
+  exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
+  rewrite <- H2. rewrite Val.and_assoc. simpl. fold p. rewrite H0. auto.
   exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
   rewrite <- H1. rewrite Val.and_assoc. auto.
 (* andimm - rolm *)
+  generalize (Int.eq_spec p m0); rewrite H7; intros. 
+  exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
+  rewrite <- H2. destruct v; simpl; auto. unfold Int.rolm. 
+  rewrite Int.and_assoc. fold p; rewrite H0. auto.
   exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
   rewrite <- H1. destruct v; simpl; auto. unfold Int.rolm. rewrite Int.and_assoc. auto.
 (* orimm *)