This loop here was a lonesome instance of a CAS loop in which adding _mm_pause() was simple, because the code didn't use the usual pattern do { construct new value } while (!testAndSet) we use everywhere else in Qt. In search of an elegant pattern that would allow to apply qYieldCpu()/_mm_pause() to those idiomatic CAS loops, too, I've reached for a lambda to construct the new value. This should apply to all (tight) CAS loops, and may form the basis of an API extension whereby we take that lambda as a function argument to encapsulate the CAS loop in an algorithm (a function). Pick-to: 6.3 Change-Id: Id4a8f174dd812aa26f0b163e943bd4558e5e6a7b Reviewed-by: Thiago Macieira <thiago.macieira@intel.com> Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>