From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20796 invoked by alias); 12 Jan 2012 09:08:32 -0000 Received: (qmail 20786 invoked by uid 22791); 12 Jan 2012 09:08:31 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 12 Jan 2012 09:08:19 +0000 From: "prasoonsaurav.nit at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/51834] -Wsequence-point fails when convoluted expressions with multiple side effects are used Date: Thu, 12 Jan 2012 09:08:00 -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: prasoonsaurav.nit at gmail dot com X-Bugzilla-Status: RESOLVED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2012-01/txt/msg01350.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51834 --- Comment #2 from Prasoon 2012-01-12 09:07:52 UTC --- @Richard Guenther Considering the expression i += (i,i++,i) +i; (i,i++,i) involves change in the value of i, however comma introduces a sequence point so very roughly considering it equivalent to func(_some_side_effect_on_i) we have i += func(_some_side_effect_on_i) + i; Do you still think the behavior is well defined? Another C++ example would be ++a = 10; where 'a'is of type int. This invokes UB but there is no warning from the compiler side even after we use this flag. Raising a similar bug for C++ because the differ may be different in C and C++. Thanks Prasoon