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From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/30364] [4.1/4.2/4.3 Regression] Wrong variable ranges due to constant folding
Date: Fri, 05 Jan 2007 19:58:00 -0000 [thread overview]
Message-ID: <20070105195835.4176.qmail@sourceware.org> (raw)
In-Reply-To: <bug-30364-7904@http.gcc.gnu.org/bugzilla/>
------- Comment #6 from pinskia at gcc dot gnu dot org 2007-01-05 19:58 -------
(In reply to comment #5)
> Do the parenthesis matter in C? They do matter in say Fortran, but in C I
> think
> (a - 20) + (b - 20) can be evaluated as (a + b) + (-20 + -20) or a - 20 - 20 +
> b
> etc.
In fact, a-20 + c will be valid even if a+c overflows but (a-20) + c does not.
There are comments in the standard somewhere which makes a mention of this.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30364
next prev parent reply other threads:[~2007-01-05 19:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-04 9:16 [Bug c/30364] New: " guillaume dot melquiond at ens-lyon dot fr
2007-01-04 9:30 ` [Bug middle-end/30364] [4.1/4.2/4.3 Regression] " pinskia at gcc dot gnu dot org
2007-01-04 10:15 ` guillaume dot melquiond at ens-lyon dot fr
2007-01-04 10:23 ` pinskia at gcc dot gnu dot org
2007-01-04 10:26 ` pinskia at gcc dot gnu dot org
2007-01-04 10:40 ` pinskia at gcc dot gnu dot org
2007-01-04 11:25 ` guillaume dot melquiond at ens-lyon dot fr
2007-01-05 19:06 ` jakub at gcc dot gnu dot org
2007-01-05 19:58 ` pinskia at gcc dot gnu dot org [this message]
2007-01-05 20:32 ` pinskia at gcc dot gnu dot org
2007-01-05 21:06 ` gdr at integrable-solutions dot net
2007-01-05 21:09 ` gdr at integrable-solutions dot net
2007-02-05 5:50 ` mmitchel at gcc dot gnu dot org
2007-02-14 9:03 ` mmitchel at gcc dot gnu dot org
2007-02-21 14:24 ` rguenth at gcc dot gnu dot org
2007-02-28 21:57 ` rguenth at gcc dot gnu dot org
2007-02-28 23:03 ` [Bug middle-end/30364] [4.1/4.2 " rguenth at gcc dot gnu dot org
2007-03-05 13:15 ` rguenth at gcc dot gnu dot org
2007-03-05 13:17 ` [Bug middle-end/30364] [4.1 " rguenth at gcc dot gnu dot org
2007-03-15 18:09 ` rguenth at gcc dot gnu dot org
2007-03-15 18:10 ` rguenth at gcc dot gnu dot org
2007-08-24 16:33 ` jakub at gcc dot gnu dot org
2007-08-24 16:40 ` rguenth at gcc dot gnu dot org
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