diff --git a/src/hb-ot-shape-complex-arabic.cc b/src/hb-ot-shape-complex-arabic.cc
index 56ec5cd..57ffc1d 100644
--- a/src/hb-ot-shape-complex-arabic.cc
+++ b/src/hb-ot-shape-complex-arabic.cc
@@ -540,7 +540,7 @@
       /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */
       hb_position_t extra_repeat_overlap = 0;
       hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1);
-      if (shortfall > 0)
+      if (shortfall > 0 && n_repeating > 0)
       {
         ++n_copies;
         hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining;