[Bug c/54340] New: internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[Bug c/54340] New: internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[socketpair at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54340

             Bug #: 54340
           Summary: internal compiler error: Illegal instruction (int
                    main() returns nothing, only when -O2/-O3 used)
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: socketpair@gmail.com


$ gcc --version
gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc test.c 

$ LANG=C gcc -O2 test.c 
test.c: In function 'main':
test.c:6:1: internal compiler error: Illegal instruction
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-4.6/README.Bugs> for instructions.
Preprocessed source stored into /tmp/ccYojEN6.out file, please attach this to
your bugreport.

$ cat test.c 
int main (void)
{
  volatile int a;
  if (a == 42)
    return 1;
}

--------------------------------
If I add "return 0;" to the end of function - problem is fixed. I understand,
that program is not correct, but, as I think, gcc should not fail on that. It
seems, it is optimizer bug.

[Bug c/54340] internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54340

--- Comment #1 from Mikael Pettersson <mikpe at it dot uu.se> 2012-08-21 07:22:09 UTC ---
You didn't specify the host, but since it's Ubuntu I'm guessing Linux/x86_64.  

I can't reproduce the SIGILL with either 4.7.1, 4.6.3, or 4.5.4 on a Core i7.

Can you reproduce with a gcc built from unpatched upstream sources?  If not
then you should report this to Ubuntu as their gcc is a heavily modified
version.

[Bug c/54340] internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54340

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |arm-linux-gnueabi

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-08-21 07:30:29 UTC ---
I think this is a Linaro toolchain which means you should report this to Ubuntu
and they will most likely report this to Linaro.

[Bug c/54340] internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[socketpair at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54340

--- Comment #3 from Коренберг Марк <socketpair at gmail dot com> 2012-08-21 07:32:25 UTC ---
Yes, I tested on gentoo, no error appear.

I have reported to ubuntu bug tracker:
https://bugs.launchpad.net/ubuntu/+source/gcc-4.6/+bug/1039401

[Bug c/54340] internal compiler error: Illegal instruction (int main() returns nothing, only when -O2/-O3 used)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54340

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-21 08:00:18 UTC ---
.