From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 2D7C0395A829; Thu, 23 Apr 2020 18:36:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 2D7C0395A829 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1587666965; bh=GRJS28acVYQZz31FcKWddsb0tQ939hqGWKtGlMhsBZ0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Dxoc5GbNJoXaGv8/YWcBzAAX7hE6y0R7hTz2QFn3HLzHm1du4GFLGx717TPyne7xN vXyMMX8kUey0SAT1C5e+Ow55acYTnnzI0DJlkqtFg4K2J4obL3xNDcVGayvhLi0UXK AjqtGXMbkf7ZhwoGyBv0iayzgltd7RJfbSuWFlGU= From: "vincent-gcc at vinc17 dot net" To: gcc-bugs@gcc.gnu.org Subject: [Bug analyzer/94732] Analyzer: false positive in MPFR's atan.c Date: Thu, 23 Apr 2020 18:36:05 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: analyzer X-Bugzilla-Version: 10.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: vincent-gcc at vinc17 dot net X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: dmalcolm 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: 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: Thu, 23 Apr 2020 18:36:05 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94732 --- Comment #1 from Vincent Lef=C3=A8vre --- Here's the corresponding simple testcase: typedef struct { int *a; } S; int *f (void); static void g (S *x) { int *p =3D x->a; p[0] =3D 0; } void h (void) { S x[1]; x->a =3D f (); g (x); } $ gcc-10 -c -fanalyzer bug.i bug.i: In function =E2=80=98g=E2=80=99: bug.i:6:8: warning: use of uninitialized value =E2=80=98p=E2=80=99 [CWE-457] [-Wanalyzer-use-of-uninitialized-value] 6 | p[0] =3D 0; | ~~~~~^~~ =E2=80=98h=E2=80=99: events 1-2 | | 8 | void h (void) | | ^ | | | | | (1) entry to =E2=80=98h=E2=80=99 |...... | 12 | g (x); | | ~~~~~ | | | | | (2) calling =E2=80=98g=E2=80=99 from =E2=80=98h=E2=80=99 | +--> =E2=80=98g=E2=80=99: events 3-4 | | 3 | static void g (S *x) | | ^ | | | | | (3) entry to =E2=80=98g=E2=80=99 |...... | 6 | p[0] =3D 0; | | ~~~~~~~~=20=20=20 | | | | | (4) use of uninitialized value =E2=80=98p=E2=80= =99 here |=