diff --git a/src/core/codecs/qtextcodec.cpp b/src/core/codecs/qtextcodec.cpp
index 697ed2c7e..a95ad387e 100644
--- a/src/core/codecs/qtextcodec.cpp
+++ b/src/core/codecs/qtextcodec.cpp
@@ -438,7 +438,7 @@ static void setup()
 
 
 #ifdef Q_DEBUG_TEXTCODEC
-    if (destroying_is_ok)
+    if (Q_UNLIKELY(destroying_is_ok))
         qWarning("QTextCodec: Creating new codec during codec cleanup");
 #endif
     all = new QList<QTextCodec*>;
@@ -655,7 +655,7 @@ QTextCodec::QTextCodec()
 QTextCodec::~QTextCodec()
 {
 #ifdef Q_DEBUG_TEXTCODEC
-    if (!destroying_is_ok)
+    if (Q_UNLIKELY(!destroying_is_ok))
         qWarning("QTextCodec::~QTextCodec: Called by application");
 #endif
     if (all) {
diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index cb4b4e262..1abd1e6dd 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -693,7 +693,7 @@ static char *aargv[] = { (char*)"unknown", 0 };
 QApplication::QApplication(Display* dpy, Qt::HANDLE visual, Qt::HANDLE colormap)
     : QCoreApplication(*new QApplicationPrivate(aargc, aargv, QApplication::Gui))
 {
-    if (! dpy)
+    if (Q_UNLIKELY(!dpy))
         qWarning("QApplication: Invalid Display* argument");
     Q_D(QApplication);
     d->construct(dpy, visual, colormap);
@@ -717,7 +717,7 @@ QApplication::QApplication(Display *dpy, int &argc, char **argv,
                            Qt::HANDLE visual, Qt::HANDLE colormap)
     : QCoreApplication(*new QApplicationPrivate(argc, argv, QApplication::Gui))
 {
-    if (! dpy)
+    if (Q_UNLIKELY(!dpy))
         qWarning("QApplication: Invalid Display* argument");
     Q_D(QApplication);
     d->construct(dpy, visual, colormap);;
@@ -1277,7 +1277,7 @@ QString QApplication::graphicsSystem()
 
 void QApplication::setGraphicsSystem(const QString &system)
 {
-    if (system == QLatin1String("native")) {
+    if (Q_UNLIKELY(system == QLatin1String("native"))) {
         qWarning() << "Attempt to set native graphicssystem";
         QApplicationPrivate::graphics_system_name = QLatin1String("raster");
     } else {
@@ -2665,7 +2665,7 @@ QDesktopWidget *QApplication::desktop()
 QClipboard *QApplication::clipboard()
 {
     if (qt_clipboard == 0) {
-        if (!qApp) {
+        if (Q_UNLIKELY(!qApp)) {
             qWarning("QApplication: Must construct a QApplication before accessing a QClipboard");
             return 0;
         }
@@ -3202,7 +3202,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
     if (QApplicationPrivate::is_app_closing)
         return true;
 
-    if (receiver == 0) {                        // serious error
+    if (Q_UNLIKELY(receiver == 0)) {                        // serious error
         qWarning("QApplication::notify: Unexpected null receiver");
         return true;
     }
@@ -3420,7 +3420,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
                         QObject *obj = d->eventFilters.at(i);
                         if (!obj)
                             continue;
-                        if (obj->d_func()->threadData != w->d_func()->threadData) {
+                        if (Q_UNLIKELY(obj->d_func()->threadData != w->d_func()->threadData)) {
                             qWarning("QApplication: Object event filter cannot be in a different thread.");
                             continue;
                         }
diff --git a/src/gui/painting/qpaintdevice.cpp b/src/gui/painting/qpaintdevice.cpp
index 27538f720..89b90dadd 100644
--- a/src/gui/painting/qpaintdevice.cpp
+++ b/src/gui/painting/qpaintdevice.cpp
@@ -50,7 +50,7 @@ QPaintDevice::QPaintDevice()
 
 QPaintDevice::~QPaintDevice()
 {
-    if (paintingActive())
+    if (Q_UNLIKELY(paintingActive()))
         qWarning("QPaintDevice: Cannot destroy paint device that is being "
                   "painted");
 }
diff --git a/src/gui/painting/qpainterpath.cpp b/src/gui/painting/qpainterpath.cpp
index 00106a029..f3dde9d48 100644
--- a/src/gui/painting/qpainterpath.cpp
+++ b/src/gui/painting/qpainterpath.cpp
@@ -636,7 +636,7 @@ void QPainterPath::moveTo(const QPointF &p)
     printf("QPainterPath::moveTo() (%.2f,%.2f)\n", p.x(), p.y());
 #endif
 
-    if (!qIsFinite(p.x()) || !qIsFinite(p.y())) {
+    if (Q_UNLIKELY(!qIsFinite(p.x()) || !qIsFinite(p.y()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::moveTo: Adding point where x or y is NaN or Inf, ignoring call");
 #endif
@@ -686,7 +686,7 @@ void QPainterPath::lineTo(const QPointF &p)
     printf("QPainterPath::lineTo() (%.2f,%.2f)\n", p.x(), p.y());
 #endif
 
-    if (!qIsFinite(p.x()) || !qIsFinite(p.y())) {
+    if (Q_UNLIKELY(!qIsFinite(p.x()) || !qIsFinite(p.y()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::lineTo: Adding point where x or y is NaN or Inf, ignoring call");
 #endif
@@ -745,8 +745,8 @@ void QPainterPath::cubicTo(const QPointF &c1, const QPointF &c2, const QPointF &
            c1.x(), c1.y(), c2.x(), c2.y(), e.x(), e.y());
 #endif
 
-    if (!qIsFinite(c1.x()) || !qIsFinite(c1.y()) || !qIsFinite(c2.x()) || !qIsFinite(c2.y())
-        || !qIsFinite(e.x()) || !qIsFinite(e.y())) {
+    if (Q_UNLIKELY(!qIsFinite(c1.x()) || !qIsFinite(c1.y()) || !qIsFinite(c2.x()) || !qIsFinite(c2.y())
+        || !qIsFinite(e.x()) || !qIsFinite(e.y()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::cubicTo: Adding point where x or y is NaN or Inf, ignoring call");
 #endif
@@ -802,7 +802,7 @@ void QPainterPath::quadTo(const QPointF &c, const QPointF &e)
            c.x(), c.y(), e.x(), e.y());
 #endif
 
-    if (!qIsFinite(c.x()) || !qIsFinite(c.y()) || !qIsFinite(e.x()) || !qIsFinite(e.y())) {
+    if (Q_UNLIKELY(!qIsFinite(c.x()) || !qIsFinite(c.y()) || !qIsFinite(e.x()) || !qIsFinite(e.y()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::quadTo: Adding point where x or y is NaN or Inf, ignoring call");
 #endif
@@ -873,8 +873,8 @@ void QPainterPath::arcTo(const QRectF &rect, qreal startAngle, qreal sweepLength
            rect.x(), rect.y(), rect.width(), rect.height(), startAngle, sweepLength);
 #endif
 
-    if ((!qIsFinite(rect.x()) && !qIsFinite(rect.y())) || !qIsFinite(rect.width()) || !qIsFinite(rect.height())
-        || !qIsFinite(startAngle) || !qIsFinite(sweepLength)) {
+    if (Q_UNLIKELY((!qIsFinite(rect.x()) && !qIsFinite(rect.y())) || !qIsFinite(rect.width()) || !qIsFinite(rect.height())
+        || !qIsFinite(startAngle) || !qIsFinite(sweepLength))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::arcTo: Adding arc where a parameter is NaN or Inf, ignoring call");
 #endif
@@ -979,7 +979,7 @@ QPointF QPainterPath::currentPosition() const
 */
 void QPainterPath::addRect(const QRectF &r)
 {
-    if (!qIsFinite(r.x()) || !qIsFinite(r.y()) || !qIsFinite(r.width()) || !qIsFinite(r.height())) {
+    if (Q_UNLIKELY(!qIsFinite(r.x()) || !qIsFinite(r.y()) || !qIsFinite(r.width()) || !qIsFinite(r.height()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::addRect: Adding rect where a parameter is NaN or Inf, ignoring call");
 #endif
@@ -1062,8 +1062,8 @@ void QPainterPath::addPolygon(const QPolygonF &polygon)
 */
 void QPainterPath::addEllipse(const QRectF &boundingRect)
 {
-    if (!qIsFinite(boundingRect.x()) || !qIsFinite(boundingRect.y())
-        || !qIsFinite(boundingRect.width()) || !qIsFinite(boundingRect.height())) {
+    if (Q_UNLIKELY(!qIsFinite(boundingRect.x()) || !qIsFinite(boundingRect.y())
+        || !qIsFinite(boundingRect.width()) || !qIsFinite(boundingRect.height()))) {
 #ifndef QT_NO_DEBUG
         qWarning("QPainterPath::addEllipse: Adding ellipse where a parameter is NaN or Inf, ignoring call");
 #endif
@@ -2391,7 +2391,7 @@ QDataStream &operator>>(QDataStream &s, QPainterPath &p)
         s >> x;
         s >> y;
         Q_ASSERT(type >= 0 && type <= 3);
-        if (!qIsFinite(x) || !qIsFinite(y)) {
+        if (Q_UNLIKELY(!qIsFinite(x) || !qIsFinite(y))) {
 #ifndef QT_NO_DEBUG
             qWarning("QDataStream::operator>>: NaN or Inf element found in path, skipping it");
 #endif
@@ -2917,7 +2917,7 @@ static inline QBezier bezierAtT(const QPainterPath &path, qreal t, qreal *starti
 */
 QPointF QPainterPath::pointAtPercent(qreal t) const
 {
-    if (t < 0 || t > 1) {
+    if (Q_UNLIKELY(t < 0 || t > 1)) {
         qWarning("QPainterPath::pointAtPercent accepts only values between 0 and 1");
         return QPointF();
     }
@@ -2951,7 +2951,7 @@ QPointF QPainterPath::pointAtPercent(qreal t) const
 */
 qreal QPainterPath::angleAtPercent(qreal t) const
 {
-    if (t < 0 || t > 1) {
+    if (Q_UNLIKELY(t < 0 || t > 1)) {
         qWarning("QPainterPath::angleAtPercent accepts only values between 0 and 1");
         return 0;
     }
@@ -2979,7 +2979,7 @@ qreal QPainterPath::angleAtPercent(qreal t) const
 */
 qreal QPainterPath::slopeAtPercent(qreal t) const
 {
-    if (t < 0 || t > 1) {
+    if (Q_UNLIKELY(t < 0 || t > 1)) {
         qWarning("QPainterPath::slopeAtPercent accepts only values between 0 and 1");
         return 0;
     }