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* [Bug c/46460] New: shifting producing incorrect result
@ 2010-11-13 5:32 keefeg at gmail dot com
2010-11-13 6:53 ` [Bug c/46460] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: keefeg at gmail dot com @ 2010-11-13 5:32 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460
Summary: shifting producing incorrect result
Product: gcc
Version: 4.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: keefeg@gmail.com
% cat bug.c
#include <stdio.h>
int main(void) {
unsigned int ShouldBeZero;
int cnt = 32;
ShouldBeZero = 0xFFFFFFFF >> cnt;
printf("Should print 0 here: %u\n", ShouldBeZero);
return 0;
}
% cc -o bug bug.c
% ./bug
Should print 0 here: 4294967295
% cc -o bug -O3 bug.c
% ./bug
Should print 0 here: 0
% gcc -v
Using built-in specs.
Target: amd64-undermydesk-freebsd
Configured with: FreeBSD/amd64 system compiler
Thread model: posix
gcc version 4.2.1 20070719 [FreeBSD]
% sysctl -a | grep 'hw\.model'
hw.model: AMD Phenom(tm) II X4 955 Processor
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/46460] shifting producing incorrect result
2010-11-13 5:32 [Bug c/46460] New: shifting producing incorrect result keefeg at gmail dot com
@ 2010-11-13 6:53 ` pinskia at gcc dot gnu.org
2010-11-13 15:10 ` [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined manu at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2010-11-13 6:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-11-13 05:31:15 UTC ---
Shifting more than the bits in the (promoted) type is undefined.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined
2010-11-13 5:32 [Bug c/46460] New: shifting producing incorrect result keefeg at gmail dot com
2010-11-13 6:53 ` [Bug c/46460] " pinskia at gcc dot gnu.org
@ 2010-11-13 15:10 ` manu at gcc dot gnu.org
2010-11-17 9:45 ` schwab@linux-m68k.org
2014-04-29 13:06 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: manu at gcc dot gnu.org @ 2010-11-13 15:10 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |NEW
Keywords| |diagnostic
Last reconfirmed| |2010.11.13 15:06:51
CC| |manu at gcc dot gnu.org
Resolution|INVALID |
Ever Confirmed|0 |1
Summary|shifting producing |warn for shifting more than
|incorrect result |the bits in the (promoted)
| |type is undefined
Severity|normal |enhancement
--- Comment #2 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2010-11-13 15:06:51 UTC ---
REOPEN as enhancement request for a warning. (No warning in 4.4.3)
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined
2010-11-13 5:32 [Bug c/46460] New: shifting producing incorrect result keefeg at gmail dot com
2010-11-13 6:53 ` [Bug c/46460] " pinskia at gcc dot gnu.org
2010-11-13 15:10 ` [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined manu at gcc dot gnu.org
@ 2010-11-17 9:45 ` schwab@linux-m68k.org
2014-04-29 13:06 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: schwab@linux-m68k.org @ 2010-11-17 9:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460
Andreas Schwab <schwab@linux-m68k.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |lepinat at free dot fr
--- Comment #3 from Andreas Schwab <schwab@linux-m68k.org> 2010-11-17 09:45:16 UTC ---
*** Bug 46517 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined
2010-11-13 5:32 [Bug c/46460] New: shifting producing incorrect result keefeg at gmail dot com
` (2 preceding siblings ...)
2010-11-17 9:45 ` schwab@linux-m68k.org
@ 2014-04-29 13:06 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2014-04-29 13:06 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |mpolacek at gcc dot gnu.org
Resolution|--- |FIXED
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We have -fsanitize=shift for this now.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-04-29 13:06 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-11-13 5:32 [Bug c/46460] New: shifting producing incorrect result keefeg at gmail dot com
2010-11-13 6:53 ` [Bug c/46460] " pinskia at gcc dot gnu.org
2010-11-13 15:10 ` [Bug c/46460] warn for shifting more than the bits in the (promoted) type is undefined manu at gcc dot gnu.org
2010-11-17 9:45 ` schwab@linux-m68k.org
2014-04-29 13:06 ` mpolacek at gcc dot gnu.org
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