b9a9f4deee
Until C++17 (inclusive), a default-constructed std::atomic object can, officially, only be initialized with a call to std::atomic_init, for which QBasicAtomic doesn't have API. It is even unclear whether zero-initialization of static and thread-local objects will cause the object to be initialized. QRegion is using QtPrivate::RefCount, but that's just another wrapper around QBasicAtomic, so it has the same problems: it must always be initialized. So don't default-construct and then storeRelaxed() (via initializeOwned()), use NSDMI with (newly-added) Q_REFCOUNT_INITIALIZE_OWNED to avoid this dark language corner. Task-number: QTBUG-137465 Pick-to: 6.8 6.5 Change-Id: I4b765aed329211984c35c40fbc5648bf104990ce Reviewed-by: Thiago Macieira <thiago.macieira@intel.com> (cherry picked from commit 5aefe2d9a1d56f6134fcbbdff260c79082eea661) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> (cherry picked from commit 2b0ec367c75bc30762ae3482c431311518b35b7b)