diff --git a/src/tac2compile.ml b/src/tac2compile.ml
index 341e9ee..f680cac 100644
--- a/src/tac2compile.ml
+++ b/src/tac2compile.ml
@@ -1121,6 +1121,7 @@ let compile ~recursive knl =
     if recursive then get_recursive_kns knl
     else knl
   in
+  debug Pp.(fun () -> str "Compiling constants " ++ prlist_with_sep spc (Tac2print.pr_tacref Id.Set.empty) knl);
   let file, ch, prefix = get_ml_filename () in
   let kns, exts, pp = pp_code recursive prefix knl in
   let fch = Format.formatter_of_out_channel ch in