diff --git a/src/hb-vector.hh b/src/hb-vector.hh
index 397571ae9..9b52f5ca9 100644
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@@ -254,6 +254,16 @@ struct hb_vector_t
     return new_array;
   }
 
+  template <typename T = Type,
+	    hb_enable_if (hb_is_trivially_constructible(T))>
+  void
+  grow_vector (unsigned size)
+  {
+    memset (arrayZ + length, 0, (size - length) * sizeof (*arrayZ));
+    length = size;
+  }
+  template <typename T = Type,
+	    hb_enable_if (!hb_is_trivially_constructible(T))>
   void
   grow_vector (unsigned size)
   {