The last fix for get_loop_info was giving false positives. Fixing that.

1 files changed, 12 insertions, 2 deletions

diff --git a/backend/Duplicateaux.ml b/backend/Duplicateaux.ml
index 217ba1b2..498cc2c5 100644
--- a/backend/Duplicateaux.ml
+++ b/backend/Duplicateaux.ml
@@ -219,11 +219,21 @@ let get_loop_info is_loop_header bfs_order code =
         match rtl_successors inst with
         | [] -> false
         | [s] -> explore s dest
-        | [s1; s2] -> begin
+        | [s1; s2] -> let snapshot_visited = ref !visited in begin
             (* Remembering that we tried the ifso node *)
             cb_info := PTree.set src true !cb_info;
             match explore s1 dest with
-            | true -> true
+            | true -> (
+                visited := !snapshot_visited;
+                match explore s2 dest with
+                | true -> begin
+                    (* Both paths lead to a loop: we cannot predict the CB
+                     * (but the explore still succeeds) *)
+                    cb_info := PTree.remove src !cb_info;
+                    true
+                  end
+                | false -> true (* nothing to do, the explore succeeded *)
+              )
             | false -> begin
                 cb_info := PTree.set src false !cb_info;
                 match explore s2 dest with