From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30546 invoked by alias); 28 Feb 2011 19:38:23 -0000 Received: (qmail 30538 invoked by uid 22791); 28 Feb 2011 19:38:22 -0000 X-SWARE-Spam-Status: No, hits=-2.8 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; Mon, 28 Feb 2011 19:38:18 +0000 From: "msebor at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/47931] missing -Waddress warning for comparison with NULL 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: msebor at gmail 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: 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 Date: Mon, 28 Feb 2011 19:52:00 -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 X-SW-Source: 2011-02/txt/msg03134.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47931 --- Comment #1 from Martin Sebor 2011-02-28 19:38:15 UTC --- To add a suggested solution to my report: Since many (most?) comparisons will be against NULL which can be defined as either 0 or (void*)0 I think it would be best to diagnose both forms. To make it possible to easily silence the warning I suggest not diagnosing cases of comparison against a null pointer constant of the same type. I.e., like so: int i; if (&i); // warning if (&i == 0); // warning if (&i == (void*)0); // warning if (&i == (int*)0); // NO warning