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From: "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/27257] Error integer compare in g++ 4.1.0 Date: Sat, 22 Apr 2006 08:23:00 -0000 [thread overview] Message-ID: <20060422082354.30165.qmail@sourceware.org> (raw) In-Reply-To: <bug-27257-12566@http.gcc.gnu.org/bugzilla/> ------- Comment #1 from pluto at agmk dot net 2006-04-22 08:23 ------- (In reply to comment #0) > int b = 0X80000000; > if ((b - 10) < 0) b - 10 is 0xff(...)7ffffff6 and this is an integer overflow. [ cite: c++ standard / $5.5 ] if during the evaluation of an expression the result isn't mathematically defined nor in the range of representable values for its type the behaviuor is undefined, unless such an expression is a constant expression, in which case the program is ill-formed. (...) [ /cite ] so, use -fwrapv (man g++) to get not quite correct behaviour. -- pluto at agmk dot net changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pluto at agmk dot net http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27257
next prev parent reply other threads:[~2006-04-22 8:23 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2006-04-22 4:56 [Bug c++/27257] New: " johnzhang at tencent dot com 2006-04-22 8:23 ` pluto at agmk dot net [this message] 2006-04-22 15:35 ` [Bug c++/27257] " pinskia at gcc dot gnu dot org 2006-04-28 6:36 ` johnzhang at tencent dot com 2006-04-28 16:29 ` pinskia at gcc dot gnu dot org 2007-01-15 20:04 ` pinskia at gcc dot gnu dot org
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