[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 via Gcc-bugs]

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

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #51559|0                           |1
        is obsolete|                            |

--- Comment #27 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 51580
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51580&action=edit
The new v4 patch

Changes in v4:

1. Bypass redundant check when inputs have been transformed to the
equivalent canonical form with valid bit operation.