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.
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 283e219..724121f 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -433,6 +433,11 @@
#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;