diff --git a/Objects/dictobject.c b/Objects/dictobject.c
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -321,12 +321,16 @@
     register size_t i;
     register size_t perturb;
     register PyDictEntry *freeslot;
-    register size_t mask = (size_t)mp->ma_mask;
-    PyDictEntry *ep0 = mp->ma_table;
+    register size_t mask;
+    PyDictEntry *ep0;
     register PyDictEntry *ep;
     register int cmp;
     PyObject *startkey;
 
+ top:
+    mask = (size_t)mp->ma_mask;
+    ep0 = mp->ma_table;
+
     i = (size_t)hash & mask;
     ep = &ep0[i];
     if (ep->me_key == NULL || ep->me_key == key)
@@ -347,9 +351,8 @@
                     return ep;
             }
             else {
-                PyErr_SetString(PyExc_RuntimeError,
-                                "dictionary changed size during lookup");
-                return NULL;
+                /* Emulate tail recursion */
+                goto top;
             }
         }
         freeslot = NULL;
@@ -376,9 +379,8 @@
                     return ep;
             }
             else {
-                PyErr_SetString(PyExc_RuntimeError,
-                                "dictionary changed size during lookup");
-                return NULL;
+                /* Emulate tail recursion */
+                goto top;
             }
         }
         else if (ep->me_key == dummy && freeslot == NULL)