http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55131
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Component|c++ |inline-asm
Version|unknown |4.7.0
Resolution| |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-10-30
02:28:31 UTC ---
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?
