QWinEventNotifier: reinterpret 'int signaledCount' as a 'bool signaled'

In fact, this variable can take only two values: 0 and 1. By
interpreting its value as boolean, we can use relaxed store operations
instead of atomic increments. This is safe, because it's guarded by
'activateEventNotifiersPosted' variable, which already provides a
release/acquire semantic.

Change-Id: If9adb7d022f1500ee7e8b61f336d8732f9b88d4c
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp
index 792260fb98..9cf426dd73 100644
--- a/src/corelib/kernel/qeventdispatcher_win.cpp
+++ b/src/corelib/kernel/qeventdispatcher_win.cpp
@@ -877,8 +877,8 @@ void QEventDispatcherWin32::activateEventNotifiers()
         for (int i = 0; i < d->winEventNotifierList.count(); ++i) {
             QWinEventNotifier *notifier = d->winEventNotifierList.at(i);
             QWinEventNotifierPrivate *nd = QWinEventNotifierPrivate::get(notifier);
-            if (nd->signaledCount.loadRelaxed() != 0) {
-                --nd->signaledCount;
+            if (nd->signaled.loadRelaxed()) {
+                nd->signaled.storeRelaxed(false);
                 nd->unregisterWaitObject();
                 d->activateEventNotifier(notifier);
             }