Fix build
diff --git a/perf/benchmark-subset.cc b/perf/benchmark-subset.cc
index 340b50c..2b40846 100644
--- a/perf/benchmark-subset.cc
+++ b/perf/benchmark-subset.cc
@@ -132,8 +132,9 @@
       AddGlyphs(num_glyphs, subset_size, input);
     }
     break;
-    
+
     case instance:
+#ifdef HB_EXPERIMENTAL_API
     {
       hb_set_t* all_codepoints = hb_set_create ();
       hb_face_collect_unicodes (face, all_codepoints);
@@ -145,6 +146,7 @@
                                            test_input.instance_opts[i].axis_tag,
                                            test_input.instance_opts[i].axis_value);
     }
+#endif
     break;
   }