------- Comment #23 from david dot kirkby at onetel dot net 2009-07-18 14:36
-------
(In reply to comment #22)
> (In reply to comment #20)
> > buf[n] = 6;
> > memset (buf+n, 0, i + j);
> > if (buf[0] != 6)
>
> It looks like you forgot to replace the second buf[0] by buf[n].
>
Sorry, my mistake. This is the current code and it does show something
intersting.
drkir...@kestrel:[~] $ cat check2.c
#include <stdio.h>
typedef __SIZE_TYPE__ size_t;
extern void *memset (void *, const void *, size_t);
extern void abort (void);
volatile size_t i = 0x80000000U, j = 0x80000000U;
char buf[16];
int main (void)
{
int n;
for (n=0 ; n <=10;++n) {
printf("n=%d\n",n);
if (sizeof (size_t) != 4)
return 0;
buf[n] = 6;
memset (buf+n, 0, i + j);
if (buf[n] != 6)
abort ();
}
return 0;
}
On the machine with the T2+ processor, which fails the mpfr tests:
kir...@t2:[~] $ gcc -Wall check2.c
check2.c: In function 'main':
check2.c:17: warning: null argument where non-null required (argument 2)
kir...@t2:[~] $ ./a.out
n=0
n=1
Abort (core dumped)
I tried with the Sun compiler too, but that refuses to compile the code.
kir...@t2:[~] $ /opt/SUNWspro/bin/cc check2.c
"check2.c", line 2: warning: no explicit type given
"check2.c", line 2: syntax error before or at: size_t
"check2.c", line 2: warning: useless declaration
cc: acomp failed for check2.c
However, when I went back and took away all the loop stuff and dropped it to
the bare minimum.
kir...@t2:[~] $ cat check3.c
typedef __SIZE_TYPE__ size_t;
extern void *memset (void *, const void *, size_t);
extern void abort (void);
volatile size_t i = 0x80000000U, j = 0x80000000U;
char buf[16];
int main (void)
{
if (sizeof (size_t) != 4)
return 0;
buf[1] = 6;
memset (buf+1, 0, i + j);
if (buf[1] != 6)
abort ();
return 0;
}
then it does not dump core.
kir...@t2:[~] $ gcc check3.c
kir...@t2:[~] $ ./a.out
kir...@t2:[~] $
In fact, trying a few small values manually, without the loop, causes no
problem.
I also tried it on my own personal machine, a Sun Blade 2000 with the sun4u
architecture (unlike the T5240 with it's T2+ processors, which is sun4v).
drkir...@kestrel:[~] $ ./a.out
n=0
n=1
n=2
n=3
n=4
n=5
n=6
n=7
n=8
n=9
n=10
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40757
