From: Todd C. Miller <Todd.Miller@courtesan.com>
Date: Fri, 24 Aug 2007 00:28:57 +0000 (+0000)
Subject: Back out he XOR swap trick, it is slower than a temp variable on
X-Git-Tag: SUDO_1_7_0~409
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b63a4c9db0c22cb6f849646555466b8c83d8c31f;p=sudo

Back out he XOR swap trick, it is slower than a temp variable on
modern CPUs.
---

diff --git a/parse.h b/parse.h
index fe18e6e14..6d14ca3c8 100644
--- a/parse.h
+++ b/parse.h
@@ -146,13 +146,12 @@ struct defaults {
 /*
  * Append one queue (or single entry) to another using the
  * circular properties of the prev pointer to simplify the logic.
- * We use XOR to swap the two prev pointers to avoid a temp variable.
  */
 #define LIST_APPEND(h, e) do {				\
+    void *_tail = (e)->prev;				\
     (h)->prev->next = (e);				\
-    (long)(e)->prev ^= (long)(h)->prev;			\
-    (long)(h)->prev ^= (long)(e)->prev;			\
-    (long)(e)->prev ^= (long)(h)->prev;			\
+    (e)->prev = (h)->prev;				\
+    (h)->prev = _tail;					\
 } while (0)
 
 /*