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From: "drh at sqlite dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/32575] New: GCC 4.3.0 with -ftree-vrp miscompiles a single line of code in SQLite Date: Sun, 01 Jul 2007 22:07:00 -0000 [thread overview] Message-ID: <bug-32575-14787@http.gcc.gnu.org/bugzilla/> (raw) A bug reported against SQLite appears to be a case of GCC 4.3.0 miscompiling a single line of code within SQLite. The problem only appears with -O2 or -Os. The problem goes away if we add the -fno-tree-vrp option. The original bug report can be found at http://www.sqlite.org/cvstrac/tktview?tn=2469 The line of code that is miscompiled is found in the source file named vdbe.c (version 1.635) on line 4309. 4308 for(j=0; j<nRoot; j++){ 4309 aRoot[j] = pTos[-j].u.i; 4310 } 4311 aRoot[j] = 0; By setting a breakpoint on line 4311 and examining the values of aRoot[] one finds that all nRoot entries of aRoot[] are being filled from pTos[0].u.i instead of being filled from pTos[0].u.i, pTos[-1].u.i, pTos[-2].u.i, and so forth as the loop intends. I will be happy to supply any additional debugging information that might help in fixing this problem (such as vdbe.s files compiled both with and without -fno-tree-vrp). I regret that I have so far been unable to replicate this problem in a small test program. -- Summary: GCC 4.3.0 with -ftree-vrp miscompiles a single line of code in SQLite Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: critical Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: drh at sqlite dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32575
next reply other threads:[~2007-07-01 22:07 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-07-01 22:07 drh at sqlite dot org [this message] 2007-07-01 22:16 ` [Bug tree-optimization/32575] " pinskia at gcc dot gnu dot org 2007-07-01 22:52 ` [Bug c/32575] " drh at sqlite dot org 2007-07-01 23:01 ` [Bug c/32575] GCC 4.2.0 " pinskia at gcc dot gnu dot org 2007-07-22 11:43 ` drh at sqlite dot org 2007-08-28 14:55 ` [Bug c/32575] [4.2/4.3 regression] With " jakub at gcc dot gnu dot org 2007-08-28 15:16 ` jakub at gcc dot gnu dot org 2007-08-28 15:58 ` jakub at gcc dot gnu dot org 2007-09-05 11:50 ` Daniel Berlin 2007-08-30 21:19 ` [Bug middle-end/32575] " pinskia at gcc dot gnu dot org 2007-09-05 0:56 ` mmitchel at gcc dot gnu dot org 2007-09-05 11:51 ` dberlin at dberlin dot org 2007-09-07 14:14 ` rguenth at gcc dot gnu dot org 2007-09-10 18:39 ` [Bug tree-optimization/32575] " jakub at gcc dot gnu dot org 2007-10-09 19:30 ` mmitchel at gcc dot gnu dot org 2007-11-01 14:03 ` nickc at redhat dot com 2007-11-01 14:06 ` nickc at redhat dot com 2007-11-01 14:34 ` jakub at gcc dot gnu dot org 2007-11-01 14:57 ` nickc at redhat dot com 2007-11-01 15:05 ` rguenth at gcc dot gnu dot org 2007-11-08 12:54 ` jakub at gcc dot gnu dot org 2007-11-08 13:08 ` jakub at gcc dot gnu dot org 2007-11-08 13:12 ` [Bug tree-optimization/32575] [4.2 " jakub at gcc dot gnu dot org 2008-02-01 17:05 ` jsm28 at gcc dot gnu dot org 2008-05-19 20:30 ` jsm28 at gcc dot gnu dot org 2009-03-30 22:11 ` jsm28 at gcc dot gnu dot org
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