[Bug tree-optimization/109407] instruction cmpxchgl run error when using with g++ -O

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109407

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

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

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The inline-asm is incorrect as the EAX/RAX register gets clobbered by cmpxchgl
So you need something like (which works now):

int tmp;
__asm__ __volatile__(
        "lock;"
        "cmpxchgl %[NEW_VALUE], %[DST];"
        "sete %[RET];"
        : [RET] "=q"(dwRtnV),[DST] "+m"(dwOriV)
        , "=a"(tmp) // newly added
        :[NEW_VALUE] "r"(dwDstV), "a"(dwExpV)
        : "memory", "cc"
);