[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 #5 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 51536
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51536&action=edit
A patch

Please try this.