* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
@ 2005-03-30 10:07 ` falk at debian dot org
2005-03-30 12:02 ` varun0005 at gmail dot com
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: falk at debian dot org @ 2005-03-30 10:07 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From falk at debian dot org 2005-03-30 10:06 -------
I don't understand what you mean. Please provide a *complete* test case,
with the command line you use and the output you get, and an explanation
of why you want a warning.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
2005-03-30 10:07 ` [Bug c/20689] " falk at debian dot org
@ 2005-03-30 12:02 ` varun0005 at gmail dot com
2005-03-30 12:24 ` falk at debian dot org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: varun0005 at gmail dot com @ 2005-03-30 12:02 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From varun0005 at gmail dot com 2005-03-30 12:02 -------
I mean that since in case where you are doing "void *p=(void *)&i" then
according to strict-aliasing rules we get " warning: dereferencing type-punned
pointer will break strict-aliasing rules" , but same thing if done using a
temporary variable then why strict-aliasing warning doesn't appear.. According
to my understanding of strict aliasing if some unqualified version of pointer is
pointing to the address space(in out case void pointer pointing to int address
space) then it is violating strict aliasing rule. So in second case also void
pointer is pointing to the int address space then why strict aliasing rules are
not violated. If ther is some error in my understanding of strict aliasing then
please inform .
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
2005-03-30 10:07 ` [Bug c/20689] " falk at debian dot org
2005-03-30 12:02 ` varun0005 at gmail dot com
@ 2005-03-30 12:24 ` falk at debian dot org
2005-03-30 15:46 ` pinskia at gcc dot gnu dot org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: falk at debian dot org @ 2005-03-30 12:24 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From falk at debian dot org 2005-03-30 12:23 -------
(In reply to comment #2)
> I mean that since in case where you are doing "void *p=(void *)&i" then
> according to strict-aliasing rules we get " warning: dereferencing type-punned
> pointer will break strict-aliasing rules"
No, you don't. Please provide a *complete* test case, with the command line
you use and the output you get.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (2 preceding siblings ...)
2005-03-30 12:24 ` falk at debian dot org
@ 2005-03-30 15:46 ` pinskia at gcc dot gnu dot org
2005-03-31 5:06 ` varun0005 at gmail dot com
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-03-30 15:46 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-03-30 15:45 -------
Also this is not done because void* cannot be dereferenced.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|WAITING |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (3 preceding siblings ...)
2005-03-30 15:46 ` pinskia at gcc dot gnu dot org
@ 2005-03-31 5:06 ` varun0005 at gmail dot com
2005-03-31 10:21 ` varun0005 at gmail dot com
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: varun0005 at gmail dot com @ 2005-03-31 5:06 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From varun0005 at gmail dot com 2005-03-31 05:05 -------
please ignore previous code and consider this piece as example ... problem is
same .the exact programs are following and command line was gcc -Wall -O2
test1.c test2.c....In this why test1.c not giving warning but test2.c giving
violation of strict-aliasing warning.
//test1.c
#include <stdio.h>
#include <stdlib.h>
int main()
{ int *i;
float **q;
int **r;
i =(int *)malloc(sizeof(int));
r=&i;
q=(float **)r;
return 0;
}
//test2.c
int main(){
int *i;
float **q;
i =(int *)malloc(sizeof(int));
q= (float **) &i;
return 0;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (4 preceding siblings ...)
2005-03-31 5:06 ` varun0005 at gmail dot com
@ 2005-03-31 10:21 ` varun0005 at gmail dot com
2005-06-30 2:21 ` pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: varun0005 at gmail dot com @ 2005-03-31 10:21 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From varun0005 at gmail dot com 2005-03-31 10:18 -------
please ignore previous code and consider this piece as example ... problem is
same .the exact programs are following and command line was gcc -Wall -O2
test1.c test2.c....In this why test1.c not giving warning but test2.c giving
violation of strict-aliasing warning.
//test1.c
#include <stdio.h>
#include <stdlib.h>
int main()
{ int *i;
float **q;
int **r;
i =(int *)malloc(sizeof(int));
r=&i;
q=(float **)r;
return 0;
}
//test2.c
int main(){
int *i;
float **q;
i =(int *)malloc(sizeof(int));
q= (float **) &i;
return 0;
}
--
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|INVALID |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (5 preceding siblings ...)
2005-03-31 10:21 ` varun0005 at gmail dot com
@ 2005-06-30 2:21 ` pinskia at gcc dot gnu dot org
2005-07-02 0:58 ` pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-06-30 2:21 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-30 02:20 -------
Even the example you gave in comment #6 is hard to get unless you have flow analysis in the front-end
which I really doubt is even going to be.
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Keywords| |diagnostic
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (6 preceding siblings ...)
2005-06-30 2:21 ` pinskia at gcc dot gnu dot org
@ 2005-07-02 0:58 ` pinskia at gcc dot gnu dot org
2005-07-11 18:00 ` pinskia at gcc dot gnu dot org
2005-07-27 23:39 ` pinskia at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-02 0:58 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-02 00:58 -------
*** Bug 20709 has been marked as a duplicate of this bug. ***
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (7 preceding siblings ...)
2005-07-02 0:58 ` pinskia at gcc dot gnu dot org
@ 2005-07-11 18:00 ` pinskia at gcc dot gnu dot org
2005-07-27 23:39 ` pinskia at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-11 18:00 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-11 17:58 -------
Closing as invalid based comment #7.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |WONTFIX
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c/20689] strict aliasing with temporary variable never gives warnings
2005-03-30 9:59 [Bug c/20689] New: strict aliasing with temporary variable never gives warnings varun0005 at gmail dot com
` (8 preceding siblings ...)
2005-07-11 18:00 ` pinskia at gcc dot gnu dot org
@ 2005-07-27 23:39 ` pinskia at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-07-27 23:39 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-27 23:39 -------
*** Bug 23106 has been marked as a duplicate of this bug. ***
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |fn_x at hotmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20689
^ permalink raw reply [flat|nested] 11+ messages in thread