From 7c862f8077e75bc841cbf1628c70f465831f2377 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 13 Dec 2007 20:50:10 +0000
Subject: Patch #1608.  Someone with access to autoconf 2.61 or higher needs to
 run it and check in the resulting configure file.

---
 Misc/ACKS    | 1 +
 Misc/NEWS    | 4 ++++
 configure.in | 6 +++++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Misc/ACKS b/Misc/ACKS
index 65ee9e7..3b968dd 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -167,6 +167,7 @@ Yves Dionne
 Daniel Dittmar
 Walter Dörwald
 Jaromir Dolecek
+Ismail Donmez
 Dima Dorfman
 Cesar Douady
 Dean Draayer
diff --git a/Misc/NEWS b/Misc/NEWS
index 7dae508..0d420d0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -1123,6 +1123,10 @@ Tools/Demos
 Build
 -----
 
+- Bug #1608: use -fwrapv when GCC supports it.  This is important,
+  newer GCC versions may optimize away overflow buffer overflow checks
+  without this option!
+
 - Patch #1418: Make the AC_REPLACE_FUNCS object files actually work.
 
 - Add a FAST_LOOPS build option that speeds-up looping by trading away
diff --git a/configure.in b/configure.in
index b0313e2..4964954 100644
--- a/configure.in
+++ b/configure.in
@@ -757,6 +757,10 @@ then
         if test "$CC" != 'g++' ; then
 	    STRICT_PROTO="-Wstrict-prototypes"
 	fi
+        # For gcc 4.x we need to use -fwrapv so lets check if its supported
+        if "$CC" -v --help 2>/dev/null |grep -- -fwrapv > /dev/null; then
+           WRAP="-fwrapv"
+        fi
 	case $ac_cv_prog_cc_g in
 	yes)
 	    if test "$Py_DEBUG" = 'true' ; then
@@ -764,7 +768,7 @@ then
 		# debug builds.
 		OPT="-g -Wall $STRICT_PROTO"
 	    else
-		OPT="-g -O3 -Wall $STRICT_PROTO"
+		OPT="-g $WRAP -O3 -Wall $STRICT_PROTO"
 	    fi
 	    ;;
 	*)
-- 
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