diff --git a/src/hb-ot-layout-gpos-table.hh b/src/hb-ot-layout-gpos-table.hh
index 48f0a9dd66086742e27b3daa2e5abe740540ce5d..c8020d87ca77da66b94ca3032a1fb0c9e5dbff81 100644
--- a/src/hb-ot-layout-gpos-table.hh
+++ b/src/hb-ot-layout-gpos-table.hh
@@ -1311,7 +1311,7 @@ struct PosLookupSubTable
   inline bool can_use_fast_path (unsigned int lookup_type) const
   {
     /* Fast path, for those that have coverage in the same place. */
-    return likely (lookup_type < Context) ||
+    return likely (lookup_type && lookup_type < Context) ||
 	   (hb_in_range<unsigned int> (lookup_type, Context, ChainContext) &&
 	    hb_in_range<unsigned int> (u.header.sub_format, 1, 2));
   }
diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index e62be98a82077d284866ae0f00e0e1d8b476e25f..f5f38cc41de0e842666885e5ef5cdb03cb333a07 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -970,7 +970,7 @@ struct SubstLookupSubTable
     /* Fast path, for those that have coverage in the same place.
      * Note that ReverseChainSingle can also go through this but
      * it's not worth the effort. */
-    return likely (lookup_type < Context) ||
+    return likely (lookup_type && lookup_type < Context) ||
 	   (hb_in_range<unsigned int> (lookup_type, Context, ChainContext) &&
 	    hb_in_range<unsigned int> (u.header.sub_format, 1, 2));
   }
diff --git a/util/shape-consumer.hh b/util/shape-consumer.hh
index 220daa497e455c0712b37a8e999c881fbe3e729c..11e4cc34a5096e615905306a86fc3dc907fc905a 100644
--- a/util/shape-consumer.hh
+++ b/util/shape-consumer.hh
@@ -49,6 +49,7 @@ struct shape_consumer_t
   {
     output.new_line ();
 
+    for (unsigned int i = 0; i < 10000; i++) {
     shaper.populate_buffer (buffer, text, text_len);
     output.consume_text (buffer, text, text_len, shaper.utf8_clusters);
 
@@ -58,6 +59,7 @@ struct shape_consumer_t
       output.shape_failed (buffer, text, text_len, shaper.utf8_clusters);
       return;
     }
+    }
 
     output.consume_glyphs (buffer, text, text_len, shaper.utf8_clusters);
   }