From: Tim Peters <tim.peters@gmail.com>
Date: Tue, 5 Sep 2006 02:18:09 +0000 (+0000)
Subject: "Conceptual" merge of rev 51711 from the 2.5 branch.
X-Git-Tag: v2.6a1~2714
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c10c9d0d6b5a5783001b4eddd309cbd33b060ade;p=python

"Conceptual" merge of rev 51711 from the 2.5 branch.

i_divmod():  As discussed on Python-Dev, changed the overflow
checking to live happily with recent gcc optimizations that
assume signed integer arithmetic never overflows.

This differs from the corresponding change on the 2.5 and 2.4
branches, using a less obscure approach, but one that /may/
tickle platform idiocies in their definitions of LONG_MIN.
The 2.4 + 2.5 change avoided introducing a dependence on
LONG_MIN, at the cost of substantially goofier code.
---

diff --git a/Misc/NEWS b/Misc/NEWS
index b4e0b2549a..04c78c0dc2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@ What's New in Python 2.6 alpha 1?
 Core and builtins
 -----------------
 
+- Overflow checking code in integer division ran afoul of new gcc
+  optimizations.  Changed to be more standard-conforming.
+
 - Patch #1542451: disallow continue anywhere under a finally.
 
 
@@ -136,7 +139,7 @@ Library
 - The __repr__ method of a NULL ctypes.py_object() no longer raises
   an exception.
 
-- uuid.UUID now has a bytes_le attribute. This returns the UUID in 
+- uuid.UUID now has a bytes_le attribute. This returns the UUID in
   little-endian byte order for Windows. In addition, uuid.py gained some
   workarounds for clocks with low resolution, to stop the code yielding
   duplicate UUIDs.
@@ -295,7 +298,7 @@ Library
 - Bug #1002398: The documentation for os.path.sameopenfile now correctly
   refers to file descriptors, not file objects.
 
-- The renaming of the xml package to xmlcore, and the import hackery done 
+- The renaming of the xml package to xmlcore, and the import hackery done
   to make it appear at both names, has been removed.  Bug #1511497,
   #1513611, and probably others.
 
diff --git a/Objects/intobject.c b/Objects/intobject.c
index c7137df40b..cbca49524e 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -565,7 +565,7 @@ i_divmod(register long x, register long y,
 		return DIVMOD_ERROR;
 	}
 	/* (-sys.maxint-1)/-1 is the only overflow case. */
-	if (y == -1 && x < 0 && x == -x)
+	if (y == -1 && x == LONG_MIN)
 		return DIVMOD_OVERFLOW;
 	xdivy = x / y;
 	xmody = x - xdivy * y;