From: Raymond Hettinger <python@rcn.com>
Date: Sun, 24 Jan 2016 20:40:42 +0000 (-0800)
Subject: Convert another post-decrement while-loop to pre-decrement for consistency
X-Git-Tag: v3.6.0a1~700
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=306d6b1ea6bf2582b9284be2fd27275abbade3e1;p=python

Convert another post-decrement while-loop to pre-decrement for consistency
and better generated code (on both GCC and CLang).
---

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index cc9e4e890e..b77ea652fb 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -895,7 +895,8 @@ deque_reverse(dequeobject *deque, PyObject *unused)
     Py_ssize_t n = Py_SIZE(deque) >> 1;
     PyObject *tmp;
 
-    while (n-- > 0) {
+    n++;
+    while (--n) {
         /* Validate that pointers haven't met in the middle */
         assert(leftblock != rightblock || leftindex < rightindex);
         CHECK_NOT_END(leftblock);