* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
@ 2007-07-25 2:43 ` pinskia at gcc dot gnu dot org
2007-07-25 2:49 ` cnstar9988 at gmail dot com
` (14 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-07-25 2:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2007-07-25 02:43 -------
What is the warning that you are expecting? We don't warn at all for memset
with a zero size.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |middle-end
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
2007-07-25 2:43 ` [Bug middle-end/32887] " pinskia at gcc dot gnu dot org
@ 2007-07-25 2:49 ` cnstar9988 at gmail dot com
2007-07-25 9:09 ` pinskia at gcc dot gnu dot org
` (13 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-25 2:49 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from cnstar9988 at gmail dot com 2007-07-25 02:49 -------
why gcc show warnings on x86.
not show warnings on x64?
Bug?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
2007-07-25 2:43 ` [Bug middle-end/32887] " pinskia at gcc dot gnu dot org
2007-07-25 2:49 ` cnstar9988 at gmail dot com
@ 2007-07-25 9:09 ` pinskia at gcc dot gnu dot org
2007-07-25 9:13 ` cnstar9988 at gmail dot com
` (12 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-07-25 9:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from pinskia at gcc dot gnu dot org 2007-07-25 09:09 -------
(In reply to comment #2)
> why gcc show warnings on x86.
I am saying this does not warn in a normal FSF GCC release. So what warning do
you expect? A warning for a zero sized memset? Well the FSF GCC does not warn
for that case at all.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (2 preceding siblings ...)
2007-07-25 9:09 ` pinskia at gcc dot gnu dot org
@ 2007-07-25 9:13 ` cnstar9988 at gmail dot com
2007-07-26 2:30 ` cnstar9988 at gmail dot com
` (11 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-25 9:13 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from cnstar9988 at gmail dot com 2007-07-25 09:13 -------
I download GCC from ftp.gnu.org, 4.2.1 release.
gcc -O3 -Wall test.c
can gernerate warning on gcc-4.2.1 on x86
but no warning on gcc-4.2.1/x64. even -m32 or -m64.
I only think the behavior on both platform is the same, because of same release
of GCC.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (3 preceding siblings ...)
2007-07-25 9:13 ` cnstar9988 at gmail dot com
@ 2007-07-26 2:30 ` cnstar9988 at gmail dot com
2007-07-26 7:42 ` pinskia at gcc dot gnu dot org
` (10 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-26 2:30 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from cnstar9988 at gmail dot com 2007-07-26 02:29 -------
Why the behavior on both platform is not the same?
same code, same release of GCC.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (4 preceding siblings ...)
2007-07-26 2:30 ` cnstar9988 at gmail dot com
@ 2007-07-26 7:42 ` pinskia at gcc dot gnu dot org
2007-07-26 7:46 ` cnstar9988 at gmail dot com
` (9 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-07-26 7:42 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from pinskia at gcc dot gnu dot org 2007-07-26 07:42 -------
> can gernerate warning on gcc-4.2.1 on x86
What is the warning? Because I am not seeing it.
It might be that glibc is doing the warning. Can you paste the warning you are
getting?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (5 preceding siblings ...)
2007-07-26 7:42 ` pinskia at gcc dot gnu dot org
@ 2007-07-26 7:46 ` cnstar9988 at gmail dot com
2007-07-26 7:50 ` pinskia at gcc dot gnu dot org
` (8 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-26 7:46 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from cnstar9988 at gmail dot com 2007-07-26 07:45 -------
test.c:14: warning: statement with no effect
So I think it is gcc warning....
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (6 preceding siblings ...)
2007-07-26 7:46 ` cnstar9988 at gmail dot com
@ 2007-07-26 7:50 ` pinskia at gcc dot gnu dot org
2007-07-26 8:02 ` cnstar9988 at gmail dot com
` (7 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-07-26 7:50 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from pinskia at gcc dot gnu dot org 2007-07-26 07:50 -------
It might be, can you attach the preprocessed source? Which you can find by
adding -save-temps and it will be either end in .i or .ii. The difference in
glibc versions could be cause different warnings to show up in some cases, I
remember fixing statement with no effect for memset already in 4.2.0.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (7 preceding siblings ...)
2007-07-26 7:50 ` pinskia at gcc dot gnu dot org
@ 2007-07-26 8:02 ` cnstar9988 at gmail dot com
2007-07-26 8:10 ` pinskia at gcc dot gnu dot org
` (6 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-26 8:02 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from cnstar9988 at gmail dot com 2007-07-26 08:02 -------
Created an attachment (id=13980)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13980&action=view)
file
gcc -m32 -O3 -Wall test.c -save-temps
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (8 preceding siblings ...)
2007-07-26 8:02 ` cnstar9988 at gmail dot com
@ 2007-07-26 8:10 ` pinskia at gcc dot gnu dot org
2007-07-26 8:13 ` cnstar9988 at gmail dot com
` (5 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-07-26 8:10 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from pinskia at gcc dot gnu dot org 2007-07-26 08:10 -------
This is a bug in glibc version you are using, the warning is comming from the
expansion of a #define. Looking at the expanded version, I see that glibc is
violating C aliasing rules anyways so the code might not always work.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (9 preceding siblings ...)
2007-07-26 8:10 ` pinskia at gcc dot gnu dot org
@ 2007-07-26 8:13 ` cnstar9988 at gmail dot com
2007-07-26 8:20 ` cnstar9988 at gmail dot com
` (4 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-26 8:13 UTC (permalink / raw)
To: gcc-bugs
------- Comment #11 from cnstar9988 at gmail dot com 2007-07-26 08:13 -------
Created an attachment (id=13981)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13981&action=view)
(64bit)gcc -m32 -O3 -Wall test.c -save-temps
(64bit)gcc -m32 -O3 -Wall test.c -save-temps
In this platform, it's no warning.
why these with no warning?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] memset warning
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (10 preceding siblings ...)
2007-07-26 8:13 ` cnstar9988 at gmail dot com
@ 2007-07-26 8:20 ` cnstar9988 at gmail dot com
2007-07-26 13:57 ` [Bug middle-end/32887] warning for memset with zero size manu at gcc dot gnu dot org
` (3 subsequent siblings)
15 siblings, 0 replies; 18+ messages in thread
From: cnstar9988 at gmail dot com @ 2007-07-26 8:20 UTC (permalink / raw)
To: gcc-bugs
------- Comment #12 from cnstar9988 at gmail dot com 2007-07-26 08:20 -------
I want the warning.
but why the warning is glibc's bug?
because memset(x,19,0), is buggy code.
I need the warning.
--
cnstar9988 at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|INVALID |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] warning for memset with zero size
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (11 preceding siblings ...)
2007-07-26 8:20 ` cnstar9988 at gmail dot com
@ 2007-07-26 13:57 ` manu at gcc dot gnu dot org
2007-07-26 16:51 ` Andrew Pinski
2007-07-26 16:51 ` pinskia at gmail dot com
` (2 subsequent siblings)
15 siblings, 1 reply; 18+ messages in thread
From: manu at gcc dot gnu dot org @ 2007-07-26 13:57 UTC (permalink / raw)
To: gcc-bugs
------- Comment #13 from manu at gcc dot gnu dot org 2007-07-26 13:57 -------
(In reply to comment #12)
> I want the warning.
> but why the warning is glibc's bug?
Andrew already tried to explain. It is a side-effect of a bug in glibc.
> because memset(x,19,0), is buggy code.
> I need the warning.
I think that is a sensible feature request, am I missing something Andrew?
I hope someone will be so kind to implement it for you (or you decide to
implement it yourself).
--
manu at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |manu at gcc dot gnu dot org
Summary|memset warning |warning for memset with zero
| |size
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] warning for memset with zero size
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (12 preceding siblings ...)
2007-07-26 13:57 ` [Bug middle-end/32887] warning for memset with zero size manu at gcc dot gnu dot org
@ 2007-07-26 16:51 ` pinskia at gmail dot com
2007-07-26 16:58 ` manu at gcc dot gnu dot org
2007-09-10 14:07 ` pinskia at gcc dot gnu dot org
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gmail dot com @ 2007-07-26 16:51 UTC (permalink / raw)
To: gcc-bugs
------- Comment #14 from pinskia at gmail dot com 2007-07-26 16:51 -------
Subject: Re: warning for memset with zero size
On 26 Jul 2007 13:57:41 -0000, manu at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>
> I think that is a sensible feature request, am I missing something Andrew?
memset with a zero size is valid code.
Thanks,
Andrew Pinski
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] warning for memset with zero size
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (13 preceding siblings ...)
2007-07-26 16:51 ` pinskia at gmail dot com
@ 2007-07-26 16:58 ` manu at gcc dot gnu dot org
2007-09-10 14:07 ` pinskia at gcc dot gnu dot org
15 siblings, 0 replies; 18+ messages in thread
From: manu at gcc dot gnu dot org @ 2007-07-26 16:58 UTC (permalink / raw)
To: gcc-bugs
------- Comment #15 from manu at gcc dot gnu dot org 2007-07-26 16:58 -------
(In reply to comment #14)
> Subject: Re: warning for memset with zero size
>
> On 26 Jul 2007 13:57:41 -0000, manu at gcc dot gnu dot org
> <gcc-bugzilla@gcc.gnu.org> wrote:
> >
> > I think that is a sensible feature request, am I missing something Andrew?
>
> memset with a zero size is valid code.
>
I am not saying that is invalid. I am saying that it is a statement with no
effect. So it could be warned as we warn for: { 0; }
Perhaps memset with size 0 appears frequently in real-code as the result of
macro expansions or such. Then, this must be closed as WONTFIX and similar
requests can be directed at this PR.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread
* [Bug middle-end/32887] warning for memset with zero size
2007-07-25 1:21 [Bug c/32887] New: memset warning cnstar9988 at gmail dot com
` (14 preceding siblings ...)
2007-07-26 16:58 ` manu at gcc dot gnu dot org
@ 2007-09-10 14:07 ` pinskia at gcc dot gnu dot org
15 siblings, 0 replies; 18+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-09-10 14:07 UTC (permalink / raw)
To: gcc-bugs
------- Comment #16 from pinskia at gcc dot gnu dot org 2007-09-10 14:07 -------
*** This bug has been marked as a duplicate of 16794 ***
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32887
^ permalink raw reply [flat|nested] 18+ messages in thread