From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-411321-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 15128 invoked by alias); 7 Jan 2013 08:01:52 -0000
Received: (qmail 15011 invoked by uid 48); 7 Jan 2013 08:01:37 -0000
From: "sworddragon2 at aol dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/55892] Bogus compiler warning
Date: Mon, 07 Jan 2013 08:01:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: sworddragon2 at aol dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields: Status Resolution
Message-ID: <bug-55892-4-FJ9NNLwjJy@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-55892-4@http.gcc.gnu.org/bugzilla/>
References: <bug-55892-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2013-01/txt/msg00440.txt.bz2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55892

sworddragon2 at aol dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |

--- Comment #2 from sworddragon2 at aol dot com 2013-01-07 08:01:36 UTC ---
> Take a line which is 16 characters long.
> The first time at beginning of the loop, limit: 8; readlimit: 8.
>
> The next time, limit:0 readlimit: 0.
> The next time limit: (unsigned long)(-8) readlimit: INT32_MAX
> Warn because readlimit > 1024.

You are right, limit -= read_limit; makes anyway no sense there so I removed it
(and the compiler wanring is gone too).

But there is still something strange on the old example: Why does line 33
trigger the warning but line 34 not? The only difference between them is that
line 33 uses a stack variable and line 34 a heap variable. Both have the same
size so shouldn't this warning trigger on both lines?