From: Benjamin Peterson <benjamin@python.org>
Date: Wed, 7 Sep 2016 03:40:04 +0000 (-0700)
Subject: promote some shifts to unsigned, so as not to invoke undefined behavior
X-Git-Tag: v2.7.13rc1~164
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=89f676f30c63f1805bc3a9e9aff4fc6f0419f959;p=python

promote some shifts to unsigned, so as not to invoke undefined behavior
---

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 151ce3c558..ca609a96ae 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -2308,7 +2308,7 @@ PyUnicode_DecodeUTF32Stateful(const char *s,
        stream as-is (giving a ZWNBSP character). */
     if (bo == 0) {
         if (size >= 4) {
-            const Py_UCS4 bom = (q[iorder[3]] << 24) | (q[iorder[2]] << 16) |
+            const Py_UCS4 bom = ((unsigned int)q[iorder[3]] << 24) | (q[iorder[2]] << 16) |
                 (q[iorder[1]] << 8) | q[iorder[0]];
 #ifdef BYTEORDER_IS_LITTLE_ENDIAN
             if (bom == 0x0000FEFF) {
@@ -2378,7 +2378,7 @@ PyUnicode_DecodeUTF32Stateful(const char *s,
             /* The remaining input chars are ignored if the callback
                chooses to skip the input */
         }
-        ch = (q[iorder[3]] << 24) | (q[iorder[2]] << 16) |
+        ch = ((unsigned int)q[iorder[3]] << 24) | (q[iorder[2]] << 16) |
             (q[iorder[1]] << 8) | q[iorder[0]];
 
         if (ch >= 0x110000)