From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 542F2385803C; Tue, 5 Jan 2021 21:11:40 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 542F2385803C From: "msebor at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/98548] New: missing warning on strcmp with a nonstring member Date: Tue, 05 Jan 2021 21:11:40 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 11.0 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: Tue, 05 Jan 2021 21:11:40 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98548 Bug ID: 98548 Summary: missing warning on strcmp with a nonstring member Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- -Wstringop-overread detects the misuse of the nonstring array as a strcmp argument in f() but not in g(). Both calls should trigger a warning. $ cat b.c && gcc -O2 -S -Wall -Wextra b.c struct A { char a[4] __attribute__ ((nonstring)); char b[8]; }; int f (void) { extern struct A a; return 0 =3D=3D __builtin_strcmp (a.a, a.b); // warning (good) } int g (struct A *p) { return 0 =3D=3D __builtin_strcmp (p->a, p->b); // missing warning } b.c: In function =E2=80=98f=E2=80=99: b.c:10:15: warning: =E2=80=98__builtin_strcmp=E2=80=99 argument 1 declared = attribute =E2=80=98nonstring=E2=80=99 is smaller than the specified bound 8 [-Wstring= op-overread] 10 | return 0 =3D=3D __builtin_strcmp (a.a, a.b); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ b.c:3:8: note: argument =E2=80=98a=E2=80=99 declared here 3 | char a[4] __attribute__ ((nonstring)); | ^=