diff --git a/src/hb-aat-layout-trak-table.hh b/src/hb-aat-layout-trak-table.hh
index 7abfc3d8ca833a0bfda093ab1df811ca7ddfa697..e6b6d55e043f73573dc81708bcc397aa8bd1d6f9 100644
--- a/src/hb-aat-layout-trak-table.hh
+++ b/src/hb-aat-layout-trak-table.hh
@@ -126,8 +126,8 @@ struct TrackData
       if (size_table[size_index].to_float () >= ptem)
         break;
 
-    return round (interpolate_at (size_index ? size_index - 1 : 0, ptem,
-				  *trackTableEntry, base));
+    return roundf (interpolate_at (size_index ? size_index - 1 : 0, ptem,
+				   *trackTableEntry, base));
   }
 
   bool sanitize (hb_sanitize_context_t *c, const void *base) const