https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103069
--- Comment #13 from Hongyu Wang <wwwhhhyyy333 at gmail dot com> ---
All above glibc cases are now both relaxed by an load/cmp to skip cmpxchg under
-mrelax-cmpxchg-loop,
but for
> do
> {
> flags = THREAD_GETMEM (self, cancelhandling);
> newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
> flags & ~SETXID_BITMASK, flags);
> }
> while (flags != newval);
If we want to optimize it to lock btc, we need to know the cmpxchg lies in a
loop. So it may require an extra pass to do further analysis and optimize,
which is not a good idea to do in stage 4.
