Slight tweak: in string_hash(), if the hash hasn't been computed yet,

and if there's a pointer to an interned version of the string, use its
hash and store its hash in this object, rather than recomputing it.

Objects/stringobject.c

@@ -433,6 +433,11 @@ string_hash(a)
 #ifdef CACHE_HASH
 	if (a->ob_shash != -1)
 		return a->ob_shash;
+#ifdef INTERN_STRINGS
+	if (a->ob_sinterned != NULL)
+		return (a->ob_shash =
+			((stringobject *)(a->ob_sinterned))->ob_shash);
+#endif
 #endif
 	len = a->ob_size;
 	p = (unsigned char *) a->ob_sval;