[Bug c++/55131] Segmentation fault happened in resulting code (inline-asm) after upgraded g++ from 3.4.6 to 4.7.0

["mawenqi108 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55131

mawenqi <mawenqi108 at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
          Component|inline-asm                  |c++
            Version|4.7.0                       |unknown
         Resolution|INVALID                     |
           Severity|normal                      |blocker

--- Comment #2 from mawenqi <mawenqi108 at gmail dot com> 2012-10-30 06:22:07 UTC ---
(In reply to comment #1)
> This is not a bug.
> The produced assembly looks like:
>        movl        8(%ebp), %edi # %1
>        movl        12(%ebp), %esi# %2
>        movl        0(%esi), %eax
>        movl        4(%esi), %edx
>        movl        (%ecx), %ebx# %3
>        movl        (%eax), %ecx# %4
> 
> By the time the last statement happens, eax has already been clobbered.  You
> never said you are clobber eax in the inline-asm so it chose the 4th operand as
> being eax.  You were getting lucky in 3.4.6 with the inline-asm really,
> 
> 
> I don't see why you don't use the __sync_* (or even better the __atomic_*)
> builtins for doing the compare and swap?

Thanks a lot for your help!
This is the old legacy code. After replaced original implementation with
buildin function __atomic_compare_exchange_n, now everything is fine!
static inline bool MyAtomic_CAS64(volatile unsigned long long* tgt, 
                                    unsigned long long* old,
                                    unsigned long long rep)
{
        return __atomic_compare_exchange_n(tgt, old, rep, 
                false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
}

Thanks again!