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From: "proski at gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/53239] New: [4.7 Regression] -ftree-vrp breaks min() Date: Fri, 04 May 2012 21:41:00 -0000 [thread overview] Message-ID: <bug-53239-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53239 Bug #: 53239 Summary: [4.7 Regression] -ftree-vrp breaks min() Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: proski@gnu.org GNU Lilypond is miscompiled on Fedora 17. It manifests as a failure to process any non-trivial input. Both i386 and x86_64 are affected. $ gcc --version gcc (GCC) 4.7.0 20120502 (Red Hat 4.7.0-3) It turns out that adding -fno-tree-vrp fixes the problem. A call to min() is affected. Comparing the assembly output without and with -fno-tree-vrp shows that the generated assembly code wrongly eliminates a conditional register move after calling the compare (_ZN6Moment7compareERKS_S1_) function. The attached file was generated on i386. Credit for finding a problem in the assembly goes to David Kastrup.
next reply other threads:[~2012-05-04 21:41 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-05-04 21:41 proski at gnu dot org [this message] 2012-05-04 21:43 ` [Bug c++/53239] " proski at gnu dot org 2012-05-04 21:54 ` pinskia at gcc dot gnu.org 2012-05-04 21:55 ` pinskia at gcc dot gnu.org 2012-05-04 22:03 ` [Bug middle-end/53239] [4.7 Regression] VRP vs named value return opt pinskia at gcc dot gnu.org 2012-05-04 23:21 ` hjl.tools at gmail dot com 2012-05-07 3:22 ` proski at gnu dot org 2012-05-07 7:14 ` [Bug tree-optimization/53239] " jakub at gcc dot gnu.org 2012-05-07 7:27 ` jakub at gcc dot gnu.org 2012-05-07 9:35 ` rguenth at gcc dot gnu.org 2012-05-07 9:38 ` rguenth at gcc dot gnu.org 2012-05-07 12:36 ` proski at gnu dot org 2012-05-07 13:24 ` [Bug tree-optimization/53239] [4.7/4.8 " hjl.tools at gmail dot com 2012-05-07 13:33 ` jakub at gcc dot gnu.org 2012-05-07 13:33 ` dak at gnu dot org 2012-05-07 13:34 ` jakub at gcc dot gnu.org 2012-05-16 15:58 ` jakub at gcc dot gnu.org
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