diff -r 98a57845c8cc Objects/dictobject.c
--- a/Objects/dictobject.c	Fri Sep 09 07:38:50 2016 +0000
+++ b/Objects/dictobject.c	Fri Sep 09 20:02:22 2016 +0900
@@ -1546,6 +1546,16 @@
         return -1;
     }
     assert(dk_get_index(mp->ma_keys, hashpos) == ix);
+
+    // Split table doesn't allow deletion.  Combine it.
+    if (_PyDict_HasSplitTable(mp)) {
+        if (dictresize(mp, DK_SIZE(mp->ma_keys))) {
+            return -1;
+        }
+        ix = (mp->ma_keys->dk_lookup)(mp, key, hash, &value_addr, &hashpos);
+        assert(ix >= 0);
+    }
+
     old_value = *value_addr;
     *value_addr = NULL;
     mp->ma_used--;
@@ -1725,7 +1735,17 @@
         return NULL;
     }
 
+    // Split table doesn't allow deletion.  Combine it.
+    if (_PyDict_HasSplitTable(mp)) {
+        if (dictresize(mp, DK_SIZE(mp->ma_keys))) {
+            return NULL;
+        }
+        ix = (mp->ma_keys->dk_lookup)(mp, key, hash, &value_addr, &hashpos);
+        assert(ix >= 0);
+    }
+
     old_value = *value_addr;
+    assert(old_value != NULL);
     *value_addr = NULL;
     mp->ma_used--;
     mp->ma_version_tag = DICT_NEXT_VERSION();