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* [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator?
@ 2011-05-24 17:21 doko at ubuntu dot com
2011-05-24 17:45 ` [Bug tree-optimization/49144] " paolo.carlini at oracle dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: doko at ubuntu dot com @ 2011-05-24 17:21 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144
Summary: [4.6/4.7 regression] miscompiled reverse_iterator?
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: doko@ubuntu.com
[forwarded from http://bugs.debian.org/PR627795]
seen with 4.6 r174102 and trunk r173903
The attached test program is supposed to print -42, and does so when compiled
with g++-4.4 or g++-4.5. However, it outputs random junk when compiled with
g++-4.6:
$ g++ -Wall -O2 test.cxx
$ ./a.out
31
$ ./a.out
207
$ ./a.out
79
#include <iostream>
int f()
{
unsigned char data[3] = { 42, 42, 42 };
unsigned char *begin = data;
unsigned char *end = data + 3;
std::reverse_iterator<unsigned char *> reversed(end);
for (; begin < end; begin++, reversed++)
if (*reversed != 42)
return *reversed;
return -42;
}
int main(int argc, char ** argv)
{
std::cout << f() << "\n";
}
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug tree-optimization/49144] [4.6/4.7 regression] miscompiled reverse_iterator? 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com @ 2011-05-24 17:45 ` paolo.carlini at oracle dot com 2011-05-24 23:27 ` jakub at gcc dot gnu.org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: paolo.carlini at oracle dot com @ 2011-05-24 17:45 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144 Paolo Carlini <paolo.carlini at oracle dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2011.05.24 17:30:16 CC| |rguenth at gcc dot gnu.org Component|other |tree-optimization Ever Confirmed|0 |1 --- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-05-24 17:30:16 UTC --- Seems indeed a serious issue, note happen only at -O1 and above. Let's ask Richard to have a look. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/49144] [4.6/4.7 regression] miscompiled reverse_iterator? 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com 2011-05-24 17:45 ` [Bug tree-optimization/49144] " paolo.carlini at oracle dot com @ 2011-05-24 23:27 ` jakub at gcc dot gnu.org 2011-05-25 3:35 ` hjl.tools at gmail dot com ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: jakub at gcc dot gnu.org @ 2011-05-24 23:27 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-24 21:58:09 UTC --- Seems tree dse2 removes data[0] = 42; store. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/49144] [4.6/4.7 regression] miscompiled reverse_iterator? 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com 2011-05-24 17:45 ` [Bug tree-optimization/49144] " paolo.carlini at oracle dot com 2011-05-24 23:27 ` jakub at gcc dot gnu.org @ 2011-05-25 3:35 ` hjl.tools at gmail dot com 2011-05-25 8:58 ` rguenth at gcc dot gnu.org 2011-05-25 11:29 ` rguenth at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: hjl.tools at gmail dot com @ 2011-05-25 3:35 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144 H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |davidxl at gcc dot gnu.org Target Milestone|--- |4.6.1 --- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> 2011-05-25 02:32:27 UTC --- It is caused by revision 162587: http://gcc.gnu.org/ml/gcc-cvs/2010-07/msg00941.html ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/49144] [4.6/4.7 regression] miscompiled reverse_iterator? 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com ` (2 preceding siblings ...) 2011-05-25 3:35 ` hjl.tools at gmail dot com @ 2011-05-25 8:58 ` rguenth at gcc dot gnu.org 2011-05-25 11:29 ` rguenth at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2011-05-25 8:58 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Depends on| |48702 --- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-05-25 08:30:28 UTC --- Sounds similar to PR48702. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/49144] [4.6/4.7 regression] miscompiled reverse_iterator? 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com ` (3 preceding siblings ...) 2011-05-25 8:58 ` rguenth at gcc dot gnu.org @ 2011-05-25 11:29 ` rguenth at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2011-05-25 11:29 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49144 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Depends on|48702 | Resolution| |DUPLICATE --- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-05-25 10:33:24 UTC --- I have verified that the patches for PR48702 also fix this bug. *** This bug has been marked as a duplicate of bug 48702 *** ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-05-25 11:07 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-05-24 17:21 [Bug other/49144] New: [4.6/4.7 regression] miscompiled reverse_iterator? doko at ubuntu dot com 2011-05-24 17:45 ` [Bug tree-optimization/49144] " paolo.carlini at oracle dot com 2011-05-24 23:27 ` jakub at gcc dot gnu.org 2011-05-25 3:35 ` hjl.tools at gmail dot com 2011-05-25 8:58 ` rguenth at gcc dot gnu.org 2011-05-25 11:29 ` rguenth at gcc dot gnu.org
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