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* [Bug c++/53462] New: template method constant folding division-by-zero warning within dead code
@ 2012-05-23 17:51 rikaigcc at rikai dot com
2012-05-23 18:13 ` [Bug c++/53462] " paolo.carlini at oracle dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: rikaigcc at rikai dot com @ 2012-05-23 17:51 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53462
Bug #: 53462
Summary: template method constant folding division-by-zero
warning within dead code
Classification: Unclassified
Product: gcc
Version: 4.4.6
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: rikaigcc@rikai.com
This code:
#include <stdio.h>
template <int I> struct foo {
static void bar() {
if (I && 10/I > 2) {
printf("Hello world\n");
}
}
};
int main(int, char**) {
foo<0>::bar();
return(0);
}
yields:
/tmp/t.cc: In static member function ‘static void foo<I>::bar() [with int I =
0]’:
/tmp/t.cc:10: instantiated from here
/tmp/t.cc:4: warning: division by zero
(but the division by zero is protected).
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/53462] template method constant folding division-by-zero warning within dead code
2012-05-23 17:51 [Bug c++/53462] New: template method constant folding division-by-zero warning within dead code rikaigcc at rikai dot com
@ 2012-05-23 18:13 ` paolo.carlini at oracle dot com
2012-05-23 18:52 ` rudick at gmail dot com
2012-05-24 0:44 ` paolo.carlini at oracle dot com
2 siblings, 0 replies; 4+ messages in thread
From: paolo.carlini at oracle dot com @ 2012-05-23 18:13 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53462
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC|rikaigcc at rikai dot com |
Resolution| |DUPLICATE
--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-05-23 18:10:57 UTC ---
This is fixed in mainline by the patch which fixed PR11856
*** This bug has been marked as a duplicate of bug 11856 ***
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/53462] template method constant folding division-by-zero warning within dead code
2012-05-23 17:51 [Bug c++/53462] New: template method constant folding division-by-zero warning within dead code rikaigcc at rikai dot com
2012-05-23 18:13 ` [Bug c++/53462] " paolo.carlini at oracle dot com
@ 2012-05-23 18:52 ` rudick at gmail dot com
2012-05-24 0:44 ` paolo.carlini at oracle dot com
2 siblings, 0 replies; 4+ messages in thread
From: rudick at gmail dot com @ 2012-05-23 18:52 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53462
--- Comment #2 from rudick at gmail dot com 2012-05-23 18:27:43 UTC ---
It looks related, but are you sure its a duplicate (if the fix was to turn
off all such warnings)?
I.e., if the code weren't made dead by being short-circuited by " if (I
&&", the warning would be appropriate & helpful.
On Wed, May 23, 2012 at 11:10 AM, paolo.carlini at oracle dot com <
gcc-bugzilla@gcc.gnu.org> wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53462
>
> Paolo Carlini <paolo.carlini at oracle dot com> changed:
>
> What |Removed |Added
>
> ----------------------------------------------------------------------------
> Status|UNCONFIRMED |RESOLVED
> CC|rikaigcc at rikai dot com |
> Resolution| |DUPLICATE
>
> --- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com>
> 2012-05-23 18:10:57 UTC ---
> This is fixed in mainline by the patch which fixed PR11856
>
> *** This bug has been marked as a duplicate of bug 11856 ***
>
> --
> Configure bugmail: http://gcc.gnu.org/bugzilla/userprefs.cgi?tab=email
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug.
> You reported the bug.
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/53462] template method constant folding division-by-zero warning within dead code
2012-05-23 17:51 [Bug c++/53462] New: template method constant folding division-by-zero warning within dead code rikaigcc at rikai dot com
2012-05-23 18:13 ` [Bug c++/53462] " paolo.carlini at oracle dot com
2012-05-23 18:52 ` rudick at gmail dot com
@ 2012-05-24 0:44 ` paolo.carlini at oracle dot com
2 siblings, 0 replies; 4+ messages in thread
From: paolo.carlini at oracle dot com @ 2012-05-24 0:44 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53462
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jason at gcc dot gnu.org
--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-05-24 00:22:29 UTC ---
Let's add Jason in CC. I seem to remember that I asked whether we wanted to be
more careful with divisions, this kind of operation. But, if we want, I'm
afraid we need a bit of infrastructural work, assuming we take false positives
seriously of course.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-05-24 0:22 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2012-05-23 17:51 [Bug c++/53462] New: template method constant folding division-by-zero warning within dead code rikaigcc at rikai dot com
2012-05-23 18:13 ` [Bug c++/53462] " paolo.carlini at oracle dot com
2012-05-23 18:52 ` rudick at gmail dot com
2012-05-24 0:44 ` paolo.carlini at oracle dot com
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