Duplicate no longer overwrites existing prediction information

1 files changed, 9 insertions, 2 deletions

diff --git a/backend/Duplicateaux.ml b/backend/Duplicateaux.ml
index 00819834..1297ec90 100644
--- a/backend/Duplicateaux.ml
+++ b/backend/Duplicateaux.ml
@@ -314,7 +314,9 @@ let get_directions code entrypoint = begin
     (* debug "\n"; *)
     List.iter (fun n ->
       match (get_some @@ PTree.get n code) with
-      | Icond (cond, lr, ifso, ifnot, _) ->
+      | Icond (cond, lr, ifso, ifnot, pred) ->
+          (match pred with Some _ -> debug "RTL node %d already has prediction information\n" (P.to_int n)
+          | None ->
           (* debug "Analyzing %d.." (P.to_int n); *)
           let heuristics = [ do_opcode_heuristic;
             do_return_heuristic; do_loop2_heuristic loop_info n; do_loop_heuristic; do_call_heuristic;
@@ -333,6 +335,7 @@ let get_directions code entrypoint = begin
                                    | None -> debug "\tUNSURE\n");
             debug "---------------------------------------\n"
           end
+          )
       | _ -> ()
     ) bfs_order;
     !directions
@@ -340,7 +343,11 @@ let get_directions code entrypoint = begin
 end
 
 let update_direction direction = function
-| Icond (cond, lr, n, n', _) -> Icond (cond, lr, n, n', direction)
+| Icond (cond, lr, n, n', pred) ->
+    (* only update if there is no prior existing branch prediction *)
+    (match pred with
+    | None -> Icond (cond, lr, n, n', direction)
+    | Some _ -> Icond (cond, lr, n, n', pred) )
 | i -> i
 
 let rec update_direction_rec directions = function