From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14161 invoked by alias); 12 May 2014 04:18:32 -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 Received: (qmail 14118 invoked by uid 48); 12 May 2014 04:18:29 -0000 From: "cloos at jhcloos dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/61144] Invalid optimizations for extern vars with local weak definitions Date: Mon, 12 May 2014 04:18:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: unknown X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: cloos at jhcloos 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-Flags: X-Bugzilla-Changed-Fields: cc 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-SW-Source: 2014-05/txt/msg00969.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D61144 James Cloos changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |cloos at jhcloos dot com --- Comment #7 from James Cloos --- This seems to be a post-4.8.2 change. (At least, it doesn=E2=80=99t show up on the Debian and Gentoo versions of = 4.8.2.) It does show up on Deb=E2=80=99s version of 4.9 and their compile from the = 4.10 branch. >>From gcc-bugs-return-451278-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon May 12 05:52:54 2014 Return-Path: Delivered-To: listarch-gcc-bugs@gcc.gnu.org Received: (qmail 645 invoked by alias); 12 May 2014 05:52:53 -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 Delivered-To: mailing list gcc-bugs@gcc.gnu.org Received: (qmail 619 invoked by uid 48); 12 May 2014 05:52:47 -0000 From: "su at cs dot ucdavis.edu" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/61150] New: wrong code at -O3 on x86_64-linux Date: Mon, 12 May 2014 05:52:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 4.10.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: su at cs dot ucdavis.edu X-Bugzilla-Status: UNCONFIRMED 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 Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-05/txt/msg00970.txt.bz2 Content-length: 1407 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61150 Bug ID: 61150 Summary: wrong code at -O3 on x86_64-linux Product: gcc Version: 4.10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu The current gcc trunk miscompiles the following code on x86_64-linux at -O3 in both 32-bit and 64-bit modes. This is a regression from 4.9.x. $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.10.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk --enable-languages=c,c++ --disable-werror --enable-multilib Thread model: posix gcc version 4.10.0 20140511 (experimental) [trunk revision 210307] (GCC) $ $ gcc-trunk -O2 small.c; a.out 0 $ gcc-4.9.0 -O3 small.c; a.out 0 $ $ gcc-trunk -O3 small.c; a.out 1 $ -------------------------------- int printf (const char *, ...); int a, b, c, d = 1; int main () { int e = d; for (b = 0; b < 5; b++) { for (a = 0; a < 1; a++) { if (e) break; for (c = 0; c < 1; c++) ; } e |= 1; } printf ("%d\n", c); return 0; }