From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 54072 invoked by alias); 19 Oct 2015 08:26:02 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 54013 invoked by uid 48); 19 Oct 2015 08:25:58 -0000 From: "fw at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/67999] Wrong optimization of pointer comparisons Date: Mon, 19 Oct 2015 08:26:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: 5.2.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: fw at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2015-10/txt/msg01464.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67999 --- Comment #8 from Florian Weimer --- (In reply to Alexander Cherepanov from comment #4) > Am I right that the C standards do not allow for such a limitation (and > hence this should not be reported to glibc as a bug) and gcc is not > standards-compliant in this regard? Or I'm missing something? The standard explicitly acknowledges the possibility of arrays that have more than PTRDIFF_MAX elements (it says that the difference of two pointers within the same array is not necessarily representable in ptrdiff_t). I'm hesitant to put in artificial limits into glibc because in the mast, there was significant demand for huge mappings in 32-bit programs (to the degree that Red Hat even shipped special kernels for this purpose).