diff --git a/src/hb-bit-page.hh b/src/hb-bit-page.hh
index 3fb188d4e..a7c788b16 100644
--- a/src/hb-bit-page.hh
+++ b/src/hb-bit-page.hh
@@ -49,7 +49,7 @@ struct hb_bit_page_t
   {
     unsigned h = 0;
     for (unsigned int i = 0; i < len (); i++)
-      h ^= hb_hash (v[i] ^ i);
+      h = h * 31 + hb_hash (v[i]);
     return h;
   }
 
diff --git a/src/hb-bit-set.hh b/src/hb-bit-set.hh
index dddaf66ab..d4a227352 100644
--- a/src/hb-bit-set.hh
+++ b/src/hb-bit-set.hh
@@ -71,7 +71,6 @@ struct hb_bit_set_t
   {
     int cmp (const page_map_t &o) const { return cmp (o.major); }
     int cmp (uint32_t o_major) const { return (int) o_major - (int) major; }
-    unsigned hash () const { return major ^ index; }
 
     uint32_t major;
     uint32_t index;
@@ -129,7 +128,10 @@ struct hb_bit_set_t
 
   unsigned hash () const
   {
-    return page_map.hash () ^ pages.hash ();
+    unsigned h = 0;
+    for (auto &map : page_map)
+      h = h * 31 + hb_hash (map.major) + hb_hash (pages[map.index]);
+    return h;
   }
 
   private: