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* [Bug tree-optimization/47708] New: incorrect code on -O2 without -fno-tree-pre
@ 2011-02-12 6:35 zephyrtronium at gmail dot com
2011-02-12 7:27 ` [Bug tree-optimization/47708] " pinskia at gmail dot com
2011-02-12 7:29 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: zephyrtronium at gmail dot com @ 2011-02-12 6:35 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47708
Summary: incorrect code on -O2 without -fno-tree-pre
Product: gcc
Version: 4.5.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: zephyrtronium@gmail.com
Created attachment 23310
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23310
minimal case
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.5.2/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.5.2/configure --enable-lto
Thread model: posix
gcc version 4.5.2 (GCC)
Compiling the following minimal case on -O2 or -O3 and running results in
incorrect output; with -O0, -O1, or -Os, it is correct. -O2 -fno-tree-pre
results in correct output, but -O1 -ftree-pre is also correct. GCC 4.4.3
appears to work.
^ permalink raw reply [flat|nested] 3+ messages in thread* [Bug tree-optimization/47708] incorrect code on -O2 without -fno-tree-pre 2011-02-12 6:35 [Bug tree-optimization/47708] New: incorrect code on -O2 without -fno-tree-pre zephyrtronium at gmail dot com @ 2011-02-12 7:27 ` pinskia at gmail dot com 2011-02-12 7:29 ` pinskia at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: pinskia at gmail dot com @ 2011-02-12 7:27 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47708 --- Comment #1 from pinskia at gmail dot com <pinskia at gmail dot com> 2011-02-12 06:36:09 UTC --- You are violating c/c++ aliasing rules. The code is undefined. Sent from my Palm Pre on AT&T On Feb 11, 2011 22:27, zephyrtronium at gmail dot com <gcc-bugzilla@gcc.gnu.org> wrote: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47708 Summary: incorrect code on -O2 without -fno-tree-pre Product: gcc Version: 4.5.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: zephyrtronium@gmail.com Created attachment 23310 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23310 minimal case gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.5.2/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.5.2/configure --enable-lto Thread model: posix gcc version 4.5.2 (GCC) Compiling the following minimal case on -O2 or -O3 and running results in incorrect output; with -O0, -O1, or -Os, it is correct. -O2 -fno-tree-pre results in correct output, but -O1 -ftree-pre is also correct. GCC 4.4.3 appears to work. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/47708] incorrect code on -O2 without -fno-tree-pre 2011-02-12 6:35 [Bug tree-optimization/47708] New: incorrect code on -O2 without -fno-tree-pre zephyrtronium at gmail dot com 2011-02-12 7:27 ` [Bug tree-optimization/47708] " pinskia at gmail dot com @ 2011-02-12 7:29 ` pinskia at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu.org @ 2011-02-12 7:29 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47708 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |DUPLICATE --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-02-12 07:26:12 UTC --- You are accessing a long long via a short. If you accessed it via a char, that would not violate aliasing rules though. *** This bug has been marked as a duplicate of bug 21920 *** ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-02-12 7:27 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-02-12 6:35 [Bug tree-optimization/47708] New: incorrect code on -O2 without -fno-tree-pre zephyrtronium at gmail dot com 2011-02-12 7:27 ` [Bug tree-optimization/47708] " pinskia at gmail dot com 2011-02-12 7:29 ` pinskia at gcc dot gnu.org
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