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* [Bug c/16309] New: different behavior in lvalue assignment in -O0 & -O2
@ 2004-07-01 8:49 nakkore at libero dot it
2004-07-01 9:08 ` [Bug c/16309] " falk at debian dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: nakkore at libero dot it @ 2004-07-01 8:49 UTC (permalink / raw)
To: gcc-bugs
Compiling with -O2 and -O0 the following code i obtain different
result with gcc version > 3.2 ( i tryed 3.3.3,3.3.4)
unsigned char dest[10],source[10]={1,2,3,4,5,6,7,8,9,10};
int main(void)
{
int i = 1;
int step = 1;
while (i < 8)
dest[i] = source[(i++*step) % 7];
for(i=0; i < 8; i++)
printf("%02x ",dest[i]);
printf("\n");
i=1;
while (i < 8)
{
dest[i] = source[(i*step) % 7];
i++;
}
for(i=0; i < 8; i++)
printf("%02x ",dest[i]);
printf("\n");
return(i+dest[6]);
}
the difference is how dest[i] is addressed via the index i.
--
Summary: different behavior in lvalue assignment in -O0 & -O2
Product: gcc
Version: 3.3.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: nakkore at libero dot it
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: Reading specs from /usr/lib/gcc-lib/i686-pc-linux-
gnu/3.3.3/spec
GCC host triplet: i386
GCC target triplet: i386
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16309
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/16309] different behavior in lvalue assignment in -O0 & -O2
2004-07-01 8:49 [Bug c/16309] New: different behavior in lvalue assignment in -O0 & -O2 nakkore at libero dot it
@ 2004-07-01 9:08 ` falk at debian dot org
2004-08-13 16:01 ` bangerth at dealii dot org
2004-08-13 16:05 ` bangerth at dealii dot org
2 siblings, 0 replies; 4+ messages in thread
From: falk at debian dot org @ 2004-07-01 9:08 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From falk at debian dot org 2004-07-01 09:08 -------
With -Wall, you get:
test.c:9: warning: operation on `i' may be undefined
and in fact it is; see documentation on -Wsequence-point.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
Summary|different behavior in lvalue|different behavior in lvalue
|assignment in -O0 & -O2 |assignment in -O0 & -O2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16309
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/16309] different behavior in lvalue assignment in -O0 & -O2
2004-07-01 8:49 [Bug c/16309] New: different behavior in lvalue assignment in -O0 & -O2 nakkore at libero dot it
2004-07-01 9:08 ` [Bug c/16309] " falk at debian dot org
@ 2004-08-13 16:01 ` bangerth at dealii dot org
2004-08-13 16:05 ` bangerth at dealii dot org
2 siblings, 0 replies; 4+ messages in thread
From: bangerth at dealii dot org @ 2004-08-13 16:01 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From bangerth at dealii dot org 2004-08-13 16:01 -------
Reopening to mark as a duplicate of...
--
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|INVALID |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16309
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/16309] different behavior in lvalue assignment in -O0 & -O2
2004-07-01 8:49 [Bug c/16309] New: different behavior in lvalue assignment in -O0 & -O2 nakkore at libero dot it
2004-07-01 9:08 ` [Bug c/16309] " falk at debian dot org
2004-08-13 16:01 ` bangerth at dealii dot org
@ 2004-08-13 16:05 ` bangerth at dealii dot org
2 siblings, 0 replies; 4+ messages in thread
From: bangerth at dealii dot org @ 2004-08-13 16:05 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From bangerth at dealii dot org 2004-08-13 16:04 -------
...PR 11751.
*** This bug has been marked as a duplicate of 11751 ***
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16309
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2004-08-13 16:04 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2004-07-01 8:49 [Bug c/16309] New: different behavior in lvalue assignment in -O0 & -O2 nakkore at libero dot it
2004-07-01 9:08 ` [Bug c/16309] " falk at debian dot org
2004-08-13 16:01 ` bangerth at dealii dot org
2004-08-13 16:05 ` bangerth at dealii dot org
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