Merge remote-tracking branch 'origin/5.12' into 5.13

Change-Id: I4c0fd501db974fb8339944b8df845336776d80a9

3 files changed, 9 insertions, 4 deletions

diff --git a/src/corelib/thread/qmutexpool.cpp b/src/corelib/thread/qmutexpool.cpp
index 3f9e8da942..bb063b8ab6 100644
--- a/src/corelib/thread/qmutexpool.cpp
+++ b/src/corelib/thread/qmutexpool.cpp
@@ -104,7 +104,7 @@ QMutexPool::QMutexPool(QMutex::RecursionMode recursionMode, int size)
 QMutexPool::~QMutexPool()
 {
     for (int index = 0; index < mutexes.count(); ++index)
-        delete mutexes[index].load();
+        delete mutexes[index].loadAcquire();
 }
 
 /*!
@@ -129,9 +129,12 @@ QMutex *QMutexPool::createMutex(int index)
 {
     // mutex not created, create one
     QMutex *newMutex = new QMutex(recursionMode);
-    if (!mutexes[index].testAndSetRelease(0, newMutex))
+    if (!mutexes[index].testAndSetRelease(nullptr, newMutex)) {
         delete newMutex;
-    return mutexes[index].load();
+        return mutexes[index].loadAcquire();
+    } else {
+        return newMutex;
+    }
 }
 
 /*!
diff --git a/src/corelib/thread/qmutexpool_p.h b/src/corelib/thread/qmutexpool_p.h
index 89d006ac29..00710199b8 100644
--- a/src/corelib/thread/qmutexpool_p.h
+++ b/src/corelib/thread/qmutexpool_p.h
@@ -68,7 +68,7 @@ public:
 
     inline QMutex *get(const void *address) {
         int index = uint(quintptr(address)) % mutexes.count();
-        QMutex *m = mutexes[index].load();
+        QMutex *m = mutexes[index].loadAcquire();
         if (m)
             return m;
         else
diff --git a/src/corelib/thread/qthread_win.cpp b/src/corelib/thread/qthread_win.cpp
index e56fe2c6ae..5c7642c26e 100644
--- a/src/corelib/thread/qthread_win.cpp
+++ b/src/corelib/thread/qthread_win.cpp
@@ -99,6 +99,8 @@ void qt_create_tls()
         return;
     static QBasicMutex mutex;
     QMutexLocker locker(&mutex);
+    if (qt_current_thread_data_tls_index != TLS_OUT_OF_INDEXES)
+        return;
     qt_current_thread_data_tls_index = TlsAlloc();
 }