This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
optimization/8376: GCC always keeps static const objects
- From: aloeff at de dot ibm dot com
- To: gcc-gnats at gcc dot gnu dot org
- Date: 28 Oct 2002 10:16:34 -0000
- Subject: optimization/8376: GCC always keeps static const objects
- Reply-to: aloeff at de dot ibm dot com
>Number: 8376
>Category: optimization
>Synopsis: GCC always keeps static const objects
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Mon Oct 28 02:26:02 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Andreas Loeffler
>Release: 3.2 (3.1, 2.96)
>Organization:
>Environment:
red hat 7.3
Reading specs from /opt/fsp/i586-pc-linux-gnu/local/lib/gcc-lib/powerpc-linux/3.2/specs
Configured with: ../configure --host=i586-pc-linux-gnu --target=powerpc-linux --prefix=/opt/fsp/i586-pc-linux-gnu/local --enable-shared --enable-languages=c,c++,f77 --with-headers=/opt/fsp/powerpc-linux/include --with-libs=/opt/fsp/powerpc-linux/lib --with-cpu=403 --without-fp
Thread model: posix
gcc version 3.2
>Description:
GCC doesn't seem to eliminate static const objects at all.
I use the following code for testing:
> --------- "x.c" --------<
static const int blah=27;
static const int yunk=93;
int foo(int num)
{
return blah*num;
}
int bar(int num)
{
return blah+num+foo(blah+num);
}
> --------- end "x.c" ----<
In this code, 'blah' should not be referenced, once optimization
took place.
'yunk' is never used. Still, GCC keeps them both in the output
file.
To verify this I tried the following command lines with GCC
3.2
powerpc-linux-gcc -O -c x.c
powerpc-linux-gcc -Os -c x.c
powerpc-linux-gcc -O3 -c x.c
powerpc-linux-gcc -fno-keep-static-consts -c x.c
In all cases, when I examine the output file with powerpc-linux-nm,
I see the symbols 'blah' and 'yunk'.
I also tried the gcc 2.96 on RedHat, with the same result.
>How-To-Repeat:
powerpc-linux-gcc -Os -c x.c
powerpc-linux-gcc -O3 -c x.c
powerpc-linux-gcc -fno-keep-static-consts -c x.c
>Fix:
?
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: application/octet-stream; name="x.c"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="x.c"
c3RhdGljIGNvbnN0IGludCBibGFoPTI3OwpzdGF0aWMgY29uc3QgaW50IHl1bms9OTM7CiAKaW50
IGZvbyhpbnQgbnVtKQp7CiAgICByZXR1cm4gYmxhaCpudW07Cn0KIAppbnQgYmFyKGludCBudW0p
CnsKICAgIHJldHVybiBibGFoK251bStmb28oYmxhaCtudW0pOwp9Cgo=