Floats.v, Nan.v: hard-wire the general shape of binop_pl, so that no axioms

are necessary, only two parameters (default_pl and choose_binop_pl).
SelectDiv: optimize FP division by a power of 2.
ConstpropOp: optimize 2.0 * x and x * 2.0 into x + x.


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2326 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e

1 files changed, 12 insertions, 1 deletions

diff --git a/ia32/SelectOp.vp b/ia32/SelectOp.vp
index 209147e..1471405 100644
--- a/ia32/SelectOp.vp
+++ b/ia32/SelectOp.vp
@@ -334,7 +334,18 @@ Definition absf (e: expr) :=  Eop Oabsf (e ::: Enil).
 Definition addf (e1 e2: expr) :=  Eop Oaddf (e1 ::: e2 ::: Enil).
 Definition subf (e1 e2: expr) :=  Eop Osubf (e1 ::: e2 ::: Enil).
 Definition mulf (e1 e2: expr) :=  Eop Omulf (e1 ::: e2 ::: Enil).
-Definition divf (e1 e2: expr) :=  Eop Odivf (e1 ::: e2 ::: Enil).
+
+Definition divfimm (e: expr) (n: float) :=
+  match Float.exact_inverse n with
+  | Some n' => Eop Omulf (e ::: Eop (Ofloatconst n') Enil ::: Enil)
+  | None    => Eop Odivf (e ::: Eop (Ofloatconst n) Enil ::: Enil)
+  end.
+
+Nondetfunction divf (e1: expr) (e2: expr) :=
+  match e2 with
+  | Eop (Ofloatconst n2) Enil => divfimm e1 n2
+  | _ => Eop Odivf (e1 ::: e2 ::: Enil)
+  end.
 
 (** ** Comparisons *)