From: Frank Peters <frank.peters@comcast.net>
To: gentoo-amd64@lists.gentoo.org
Subject: Re: [gentoo-amd64] Re: GCC-4.5.2 Has Serious Problems
Date: Thu, 30 Jun 2011 20:04:24 -0400 [thread overview]
Message-ID: <20110630200424.0d6d49ef.frank.peters@comcast.net> (raw)
In-Reply-To: <iuj1o7$o6s$2@dough.gmane.org>
On Fri, 01 Jul 2011 02:44:36 +0300
Nikos Chantziaras <realnc@arcor.de> wrote:
> >
> > Your code is buggy, because you're breaking C's aliasing rules. You are
> > not allowed to use a different pointer type to dereference a variable of
> > a different type. Doing so results in undefined behavior.
>
Well, the error occurs only within the loop structure. If
I manually "unroll" the loop using the same pointers there
is no error when compiled with "O2."
IOW, the problem is how the loop is optimized under -O2.
Frank Peters
next prev parent reply other threads:[~2011-07-01 0:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-30 21:45 [gentoo-amd64] GCC-4.5.2 Has Serious Problems Frank Peters
2011-06-30 22:30 ` Alex Schuster
2011-06-30 23:34 ` Frank Peters
2011-06-30 23:35 ` [gentoo-amd64] " Nikos Chantziaras
2011-06-30 23:44 ` Nikos Chantziaras
2011-07-01 0:04 ` Frank Peters [this message]
2011-07-01 0:11 ` Nikos Chantziaras
2011-07-01 0:58 ` Duncan
2011-07-01 1:23 ` Frank Peters
2011-07-01 1:52 ` Duncan
2011-07-01 2:15 ` Ian McCulloch
2011-07-01 4:36 ` Mark Knecht
2011-07-01 5:22 ` Frank Peters
2011-07-01 0:25 ` Frank Peters
2011-07-01 1:04 ` Frank Peters
2011-07-01 2:18 ` Duncan
2011-07-01 2:22 ` Barry Schwartz
2011-07-01 2:43 ` Frank Peters
2011-07-01 11:53 ` Nikos Chantziaras
2011-07-01 16:53 ` Frank Peters
-- strict thread matches above, loose matches on Subject: below --
2011-07-01 2:30 Ian McCulloch
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