[Bug middle-end/102566] [i386] GCC should emit LOCK BTS for simple bit-test-and-set operations with std::atomic

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102566

--- Comment #18 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Andrew Pinski from comment #16)
> (In reply to H.J. Lu from comment #14)
> > Created attachment 51556 [details]
> > The v5 patch
> > 
> > Changes in v5:
> > 
> > 1. Check SSA_NAME before SSA_NAME_OCCURS_IN_ABNORMAL_PHI.
> 
> Why don't you just move this to match.pd instead as suggested by Richard B.
> on the mailing list?  Then you get the check for
> SSA_NAME_OCCURS_IN_ABNORMAL_PHI for free and such.  Plus other passes will
> do the optimization too ....

Without __atomic_fetch_or_* or __atomic_fetch_and_*, the conversion isn't
needed.  We also need to check the mask of the atomic builtin.