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From: "tg at mirbsd dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/30477] Integer Overflow detection code optimised away, -fwrapv broken Date: Mon, 22 Jan 2007 23:54:00 -0000 [thread overview] Message-ID: <20070122235417.15056.qmail@sourceware.org> (raw) In-Reply-To: <bug-30477-13924@http.gcc.gnu.org/bugzilla/> [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain, Size: 1178 bytes --] ------- Comment #15 from tg at mirbsd dot de 2007-01-22 23:54 ------- Subject: Re: Integer Overflow detection code optimised away, -fwrapv broken pinskia at gcc dot gnu dot org dixit: >fold-const.c changed a lot, etc. >Actually there are two different code, one I wrote which is does >folding of a-10 > 0 into a>10 and other code which folds a-10>a into true, >I wrote the first one. I found the second one in CVSweb, and it's not the cause for this unsafe "optimisation". I even changed fold-const.c to have some wrapper around fold() which debug_tree()s me the input and output, and the '100' stays in (at -O1, which does exhibit the faulty behaviour already): [â¦] arg 1 <integer_cst 0xa7d85b7c constant 100>> arg 1 <parm_decl 0xa7d1cec4 a>> Now I don't know any gcc internals, but I suppose this isn't done in fold-const.c⦠thanks to fprintf, my beloved debugger ;) bye, //mirabile -- "Using Lynx is like wearing a really good pair of shades: cuts out the glare and harmful UV (ultra-vanity), and you feel so-o-o COOL." -- Henry Nelson, March 1999 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30477
next prev parent reply other threads:[~2007-01-22 23:54 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-01-15 23:43 [Bug c/30477] New: " tg at mirbsd dot org 2007-01-15 23:56 ` [Bug c/30477] " pinskia at gcc dot gnu dot org 2007-01-15 23:57 ` pinskia at gcc dot gnu dot org 2007-01-16 2:34 ` tg at mirbsd dot org 2007-01-16 3:04 ` pinskia at gmail dot com 2007-01-16 3:40 ` tg at mirbsd dot de 2007-01-16 3:48 ` Andrew Pinski 2007-01-16 3:49 ` pinskia at physics dot uc dot edu 2007-01-16 4:08 ` tg at mirbsd dot org 2007-01-16 10:36 ` rguenth at gcc dot gnu dot org 2007-01-16 16:56 ` tg at mirbsd dot org 2007-01-16 17:18 ` rguenth at gcc dot gnu dot org 2007-01-16 17:34 ` tg at mirbsd dot org 2007-01-16 17:49 ` tg at mirbsd dot org 2007-01-16 18:00 ` pinskia at gcc dot gnu dot org 2007-01-16 18:01 ` gdr at cs dot tamu dot edu 2007-01-22 23:54 ` tg at mirbsd dot de [this message] 2007-01-25 14:29 ` tg at mirbsd dot org 2007-01-25 14:50 ` rguenth at gcc dot gnu dot org 2007-01-25 16:09 ` tg at mirbsd dot org [not found] <bug-30477-4@http.gcc.gnu.org/bugzilla/> 2014-02-16 13:17 ` jackie.rosen at hushmail dot com
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