[Bug other/50916] New: -Os, -D_FORTIFY_SOURCE breaks strcpy & others if inlined

["dezgeg at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50916

             Bug #: 50916
           Summary: -Os, -D_FORTIFY_SOURCE breaks strcpy & others if
                    inlined
    Classification: Unclassified
           Product: gcc
           Version: 4.6.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dezgeg@gmail.com


Created attachment 25665
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25665
The preprocessed source

Not totally sure if a glibc or gcc bug, but anyway: GCC 4.6.2 causes the
following code to get into an infinite loop in strcpy if compiled with
gcc -std=c99 -Os -D_FORTIFY_SOURCE=2

#include <argp.h>
#include <string.h>

int main (void) {
    char buf[1024];
    char* str = "hello";
    strcpy (buf, str);
    return 0;
}

It seems that something in the #includes is pulling in the following definition
for strcpy:

extern __inline char *
 strcpy (char *__restrict __dest, const char *__restrict __src)
{
  return __builtin___strcpy_chk (__dest, __src, __builtin_object_size (__dest,
2 > 1));
}
...and then the __builtin_strcpy_chk seems to turn back into strcpy (due to
-Os?):

00000035 <strcpy>:
  35:   55                      push   %ebp
  36:   89 e5                   mov    %esp,%ebp
  38:   5d                      pop    %ebp
  39:   e9 fc ff ff ff          jmp    3a <strcpy+0x5>
                        3a: R_386_PC32  strcpy
...which then causes the infinite loop.

gcc -v:

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i486-linux-gnu/4.6/lto-wrapper
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.6.2-2'
--with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++,go --prefix=/usr
--program-suffix=-4.6 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-plugin --enable-objc-gc
--enable-targets=all --with-arch-32=i586 --with-tune=generic
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.6.2 (Debian 4.6.2-2)