[Bug rtl-optimization/23343] New: Optimization -O3 removes static const char * ident strings

Thu Aug 11 20:57:00 GMT 2005

When using gcc 3.3.3 on a Linux machine, the -O3 option is removing the static 
const char* strings we use to identify file versions.  This behavior is 
different than how the 3.2.3 versions behave.  Below is the relevant output 
that shows the differences between the 2 versions.

devbal801:<~/TEST> rm -f a.out
devbal801:<~/TEST> cat test.c
#include <stdio.h>

static const char *rcsid2 = "$Header:  Header information $";

int
main()
{
   printf("Hello World\n");
}
devbal801:<~/TEST> gcc -v -save-temps -O3 test.c
Reading specs from /usr/lib/gcc-lib/i586-suse-linux/3.3.3/specs
Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-
prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --enable-
languages=c,c++,f77,objc,java,ada --disable-checking --libdir=/usr/lib --enable-
libgcj --with-gxx-include-dir=/usr/include/g++ --with-slibdir=/lib --with-
system-zlib --enable-shared --enable-__cxa_atexit i586-suse-linux
Thread model: posix
gcc version 3.3.3 (SuSE Linux)
 /usr/lib/gcc-lib/i586-suse-linux/3.3.3/cc1 -E -quiet -v -D__GNUC__=3 -
D__GNUC_MINOR__=3 -D__GNUC_PATCHLEVEL__=3 test.c -O3 test.i
ignoring nonexistent directory "/usr/local/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc-lib/i586-suse-linux/3.3.3/include
 /usr/i586-suse-linux/include
 /usr/include
End of search list.
 /usr/lib/gcc-lib/i586-suse-linux/3.3.3/cc1 -fpreprocessed test.i -quiet -
dumpbase test.c -auxbase test -O3 -version -o test.s
GNU C version 3.3.3 (SuSE Linux) (i586-suse-linux)
        compiled by GNU C version 3.3.3 (SuSE Linux).
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129594
 /usr/lib/gcc-lib/i586-suse-linux/3.3.3/../../../../i586-suse-linux/bin/as -V -
Qy -o test.o test.s
GNU assembler version 2.15.90.0.1.1 (i586-suse-linux) using BFD version 
2.15.90.0.1.1 20040303 (SuSE Linux)
 /usr/lib/gcc-lib/i586-suse-linux/3.3.3/collect2 --eh-frame-hdr -m elf_i386 -
dynamic-linker /lib/ld-linux.so.2 /usr/lib/gcc-lib/i586-suse-
linux/3.3.3/../../../crt1.o /usr/lib/gcc-lib/i586-suse-
linux/3.3.3/../../../crti.o /usr/lib/gcc-lib/i586-suse-linux/3.3.3/crtbegin.o -
L/usr/lib/gcc-lib/i586-suse-linux/3.3.3 -L/usr/lib/gcc-lib/i586-suse-
linux/3.3.3/../../../../i586-suse-linux/lib -L/usr/lib/gcc-lib/i586-suse-
linux/3.3.3/../../.. test.o -lgcc -lgcc_eh -lc -lgcc -lgcc_eh /usr/lib/gcc-
lib/i586-suse-linux/3.3.3/crtend.o /usr/lib/gcc-lib/i586-suse-
linux/3.3.3/../../../crtn.o
devbal801:<~/TEST> ident a.out
a.out:
ident: (warning) no id keywords in a.out
devbal801:<~/TEST> rm -f a.out
devbal801:<~/TEST> /usr/local/gcc/gcc-3.2.3/bin/gcc -v -save-temps -O3 test.c
Reading specs from /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-
gnu/3.2.3/specs
Configured with: ./configure --prefix=/usr/local/gcc/gcc-3.2.3
Thread model: posix
gcc version 3.2.3
 /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-gnu/3.2.3/cpp0 -lang-c -v -
D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=3 -D__GXX_ABI_VERSION=102 -
D__ELF__ -Dunix -D__gnu_linux__ -Dlinux -D__ELF__ -D__unix__ -D__gnu_linux__ -
D__linux__ -D__unix -D__linux -Asystem=posix -D__OPTIMIZE__ -
D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -
D__tune_i686__ -D__tune_pentiumpro__ test.c test.i
GNU CPP version 3.2.3 (cpplib) (i386 Linux/ELF)
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/local/gcc/gcc-3.2.3/i686-pc-linux-
gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/gcc/gcc-3.2.3/include
 /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-gnu/3.2.3/include
 /usr/include
End of search list.
 /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-gnu/3.2.3/cc1 -
fpreprocessed test.i -quiet -dumpbase test.c -O3 -version -o test.s
GNU CPP version 3.2.3 (cpplib) (i386 Linux/ELF)
GNU C version 3.2.3 (i686-pc-linux-gnu)
        compiled by GNU C version 3.3.3 (SuSE Linux).
 as -V -Qy -o test.o test.s
GNU assembler version 2.15.90.0.1.1 (i586-suse-linux) using BFD version 
2.15.90.0.1.1 20040303 (SuSE Linux)
 /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-gnu/3.2.3/collect2 --eh-
frame-hdr -m elf_i386 -dynamic-linker /lib/ld-
linux.so.2 /usr/lib/crt1.o /usr/lib/crti.o /usr/local/gcc/gcc-3.2.3/lib/gcc-
lib/i686-pc-linux-gnu/3.2.3/crtbegin.o -L/usr/local/gcc/gcc-3.2.3/lib/gcc-
lib/i686-pc-linux-gnu/3.2.3 -L/usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-
linux-gnu/3.2.3/../../.. test.o -lgcc -lgcc_eh -lc -lgcc -
lgcc_eh /usr/local/gcc/gcc-3.2.3/lib/gcc-lib/i686-pc-linux-
gnu/3.2.3/crtend.o /usr/lib/crtn.o
devbal801:<~/TEST> ident a.out
a.out:
     $Header:  Header information $
devbal801:<~/TEST> uname -a
Linux devbal801 2.6.5-7.97-default #1 Fri Jul 2 14:21:59 UTC 2004 i686 i686 
i386 GNU/Linux
devbal801:<~/TEST>

-- 
           Summary: Optimization -O3 removes static const char * ident
                    strings
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Wempa at sig dot com
                CC: gcc-bugs at gcc dot gnu dot org

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23343