diff --git a/src/hb-aat-layout-common.hh b/src/hb-aat-layout-common.hh
index 540b2dd3b..0e694407b 100644
--- a/src/hb-aat-layout-common.hh
+++ b/src/hb-aat-layout-common.hh
@@ -65,7 +65,6 @@ struct hb_aat_apply_context_t :
   const OT::GDEF *gdef_table;
   const hb_sorted_vector_t<hb_aat_map_t::range_flags_t> *range_flags = nullptr;
   hb_set_digest_t buffer_digest = hb_set_digest_t::full ();
-  hb_set_digest_t machine_glyph_set = hb_set_digest_t::full ();
   hb_set_digest_t left_set = hb_set_digest_t::full ();
   hb_set_digest_t right_set = hb_set_digest_t::full ();
   hb_aat_class_cache_t *machine_class_cache = nullptr;
@@ -640,14 +639,12 @@ struct StateTable
   int new_state (unsigned int newState) const
   { return Types::extended ? newState : ((int) newState - (int) stateArrayTable) / (int) nClasses; }
 
-  template <typename set_t, typename cache_t>
+  template <typename cache_t>
   unsigned int get_class (hb_codepoint_t glyph_id,
 			  unsigned int num_glyphs,
-			  const set_t &glyphs,
 			  cache_t *cache) const
   {
     if (unlikely (glyph_id == DELETED_GLYPH)) return CLASS_DELETED_GLYPH;
-    if (!glyphs[glyph_id]) return CLASS_OUT_OF_BOUNDS;
     if (cache)
     {
       unsigned int klass;
@@ -948,7 +945,7 @@ struct StateTableDriver
   {
     const auto entry = machine.get_entry (StateTableT::STATE_START_OF_TEXT, CLASS_OUT_OF_BOUNDS);
     return !c->is_actionable (ac->buffer, this, entry) &&
-	    machine.new_state (entry.newState) == StateTableT::STATE_START_OF_TEXT;
+           machine.new_state (entry.newState) == StateTableT::STATE_START_OF_TEXT;
   }
 
   template <typename context_t>
@@ -991,7 +988,7 @@ struct StateTableDriver
       }
 
       unsigned int klass = likely (buffer->idx < buffer->len) ?
-			   machine.get_class (buffer->cur().codepoint, num_glyphs, ac->machine_glyph_set, ac->machine_class_cache) :
+			   machine.get_class (buffer->cur().codepoint, num_glyphs, ac->machine_class_cache) :
 			   (unsigned) CLASS_END_OF_TEXT;
       DEBUG_MSG (APPLY, nullptr, "c%u at %u", klass, buffer->idx);
       const EntryT &entry = machine.get_entry (state, klass);
diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index f9bda6b3d..6e2b33565 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -171,10 +171,6 @@ struct RearrangementSubtable
 
     StateTableDriver<Types, EntryData> driver (machine, c->face);
 
-    if (driver.is_idempotent_on_all_out_of_bounds (&dc, c) &&
-	!c->buffer_digest.may_have (c->machine_glyph_set))
-      return_trace (false);
-
     driver.drive (&dc, c);
 
     return_trace (dc.ret);
@@ -336,10 +332,6 @@ struct ContextualSubtable
 
     StateTableDriver<Types, EntryData> driver (machine, c->face);
 
-    if (driver.is_idempotent_on_all_out_of_bounds (&dc, c) &&
-	!c->buffer_digest.may_have (c->machine_glyph_set))
-      return_trace (false);
-
     driver.drive (&dc, c);
 
     return_trace (dc.ret);
@@ -599,10 +591,6 @@ struct LigatureSubtable
 
     StateTableDriver<Types, EntryData> driver (machine, c->face);
 
-    if (driver.is_idempotent_on_all_out_of_bounds (&dc, c) &&
-	!c->buffer_digest.may_have (c->machine_glyph_set))
-      return_trace (false);
-
     driver.drive (&dc, c);
 
     return_trace (dc.ret);
@@ -875,10 +863,6 @@ struct InsertionSubtable
 
     StateTableDriver<Types, EntryData> driver (machine, c->face);
 
-    if (driver.is_idempotent_on_all_out_of_bounds (&dc, c) &&
-	!c->buffer_digest.may_have (c->machine_glyph_set))
-      return_trace (false);
-
     driver.drive (&dc, c);
 
     return_trace (dc.ret);
@@ -935,25 +919,11 @@ struct hb_accelerate_subtables_context_t :
     friend struct hb_aat_layout_lookup_accelerator_t;
 
     public:
-    hb_set_digest_t digest;
     hb_aat_class_cache_t *class_cache;
 
-    template <typename T>
-    auto init_ (const T &obj_, unsigned num_glyphs, hb_priority<1>) HB_AUTO_RETURN
-    (
-      obj_.machine.collect_glyphs (this->digest, num_glyphs)
-    )
-
-    template <typename T>
-    void init_ (const T &obj_, unsigned num_glyphs, hb_priority<0>)
-    {
-      digest = digest.full ();
-    }
-
     template <typename T>
     void init (const T &obj_, unsigned num_glyphs)
     {
-      init_ (obj_, num_glyphs, hb_prioritize);
       class_cache = (hb_aat_class_cache_t *) malloc (sizeof (hb_aat_class_cache_t));
       if (class_cache)
 	class_cache->clear ();
@@ -1175,7 +1145,6 @@ struct Chain
 		   hb_map ([&subtable] (const hb_aat_map_t::range_flags_t _) -> bool { return subtable->subFeatureFlags & (_.flags); })))
 	goto skip;
       c->subtable_flags = subtable->subFeatureFlags;
-      c->machine_glyph_set = accel ? accel->subtables[i].digest : hb_set_digest_t::full ();
       c->machine_class_cache = accel ? accel->subtables[i].class_cache : nullptr;
 
       if (!(subtable->get_coverage() & ChainSubtable<Types>::AllDirections) &&