From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 37AB23858406; Fri, 1 Oct 2021 16:06:31 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 37AB23858406 From: "msebor at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/102555] New: missing -Waddress comparing &p[0] to zero Date: Fri, 01 Oct 2021 16:06:31 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: msebor 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: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Oct 2021 16:06:31 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102555 Bug ID: 102555 Summary: missing -Waddress comparing &p[0] to zero Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- Event with the patch for pr102103 applied, only the first of the two equali= ty expressions gets a warning, even though ideally both should. This is track= ed (and xfailed) in gcc/testsuite/c-c++-common/Waddress-4.c. $ cat z.c && gcc -S -Wall -fdump-tree-original=3D/dev/stdout z.c int f (int *p, int i) { return &p[i] =3D=3D 0; }=20=20=20=20=20=20 int g (int *p) { return &p[0] =3D=3D 0; } z.c: In function =E2=80=98f=E2=80=99: z.c:3:16: warning: the comparison will always evaluate as =E2=80=98false=E2= =80=99 for the pointer operand in =E2=80=98p + (sizetype)((long unsigned int)i * 4)=E2=80= =99 must not be NULL [-Waddress] 3 | return &p[i] =3D=3D 0; | ^~ ;; Function f (null) ;; enabled by -tree-original { return p + (sizetype) ((long unsigned int) i * 4) =3D=3D 0B; } ;; Function g (null) ;; enabled by -tree-original { return p =3D=3D 0B; }=