diff --git a/src/hb-ot-layout-common.hh b/src/hb-ot-layout-common.hh
index a1c2cdcb2..5de55becf 100644
--- a/src/hb-ot-layout-common.hh
+++ b/src/hb-ot-layout-common.hh
@@ -1900,13 +1900,16 @@ struct ClassDefFormat2_4
 
   bool intersects (const hb_set_t *glyphs) const
   {
-    /* TODO Speed up, using hb_set_next() and bsearch()? */
-    for (auto &range : rangeRecord)
+    if (rangeRecord.len > glyphs->get_population () * hb_bit_storage ((unsigned) rangeRecord.len) / 2)
     {
-      if (range.intersects (*glyphs) && range.value)
-	return true;
+      for (hb_codepoint_t g = HB_SET_VALUE_INVALID; glyphs->next (&g);)
+        if (get_class (g))
+	  return true;
+      return false;
     }
-    return false;
+
+    return hb_any (+ hb_iter (rangeRecord)
+                   | hb_map ([glyphs] (const RangeRecord<Types> &range) { return range.intersects (*glyphs) && range.value; }));
   }
   bool intersects_class (const hb_set_t *glyphs, uint16_t klass) const
   {