From b44c5169f64178d2ff2914187b315549e7ab0cb6 Mon Sep 17 00:00:00 2001
From: Raymond Hettinger <rhettinger@users.noreply.github.com>
Date: Tue, 16 Jan 2018 01:30:26 -0800
Subject: bpo-26163: Frozenset hash improvement (#5194)

---
 Objects/setobject.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'Objects/setobject.c')

diff --git a/Objects/setobject.c b/Objects/setobject.c
index c920fb9853..4bc1020d56 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -795,6 +795,7 @@ frozenset_hash(PyObject *self)
     hash ^= ((Py_uhash_t)PySet_GET_SIZE(self) + 1) * 1927868237UL;
 
     /* Disperse patterns arising in nested frozensets */
+    hash ^= (hash >> 11) ^ (~hash >> 25);
     hash = hash * 69069U + 907133923UL;
 
     /* -1 is reserved as an error code */
-- 
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