Index: Python/ceval.c
===================================================================
--- Python/ceval.c	(revision 64156)
+++ Python/ceval.c	(working copy)
@@ -2753,6 +2753,7 @@
 			}
 		}
 		for (i = 0; i < kwcount; i++) {
+			PyObject **co_varnames;
 			PyObject *keyword = kws[2*i];
 			PyObject *value = kws[2*i + 1];
 			int j;
@@ -2762,14 +2763,20 @@
 				    PyString_AsString(co->co_name));
 				goto fail;
 			}
-			/* XXX slow -- speed up using dictionary? */
+			/* Speed hack: do raw pointer compares. As names are
+			   normally interned this should almost always hit. */
+			co_varnames = PySequence_Fast_ITEMS(co->co_varnames);
 			for (j = 0; j < co->co_argcount; j++) {
-				PyObject *nm = PyTuple_GET_ITEM(
-					co->co_varnames, j);
-				int cmp = PyObject_RichCompareBool(
-					keyword, nm, Py_EQ);
+				PyObject *nm = co_varnames[j];
+				if (nm == keyword)
+					goto kw_found;
+			}
+			/* Slow fallback, just in case */
+			for (j = 0; j < co->co_argcount; j++) {
+				PyObject *nm = co_varnames[j];
+				int cmp = PyObject_RichCompareBool(keyword, nm, Py_EQ);
 				if (cmp > 0)
-					break;
+					goto kw_found;
 				else if (cmp < 0)
 					goto fail;
 			}
@@ -2786,20 +2793,20 @@
 					goto fail;
 				}
 				PyDict_SetItem(kwdict, keyword, value);
+				continue;
 			}
-			else {
-				if (GETLOCAL(j) != NULL) {
-					PyErr_Format(PyExc_TypeError,
-					     "%.200s() got multiple "
-					     "values for keyword "
-					     "argument '%.400s'",
-					     PyString_AsString(co->co_name),
-					     PyString_AsString(keyword));
-					goto fail;
-				}
-				Py_INCREF(value);
-				SETLOCAL(j, value);
+kw_found:
+			if (GETLOCAL(j) != NULL) {
+				PyErr_Format(PyExc_TypeError,
+						"%.200s() got multiple "
+						"values for keyword "
+						"argument '%.400s'",
+						PyString_AsString(co->co_name),
+						PyString_AsString(keyword));
+				goto fail;
 			}
+			Py_INCREF(value);
+			SETLOCAL(j, value);
 		}
 		if (argcount < co->co_argcount) {
 			int m = co->co_argcount - defcount;