QtWidgets: use Q_UNLIKELY for every qWarning() (1)

If, after checking a condition, we issue a qWarning(),
by definition that check is unlikely to be true.

Tell the compiler so it can move the error handling
code out of the normal code path to increase the
effective icache size.

This change contains the changes to the util/,
dialogs/ and widgets/ subdirs.

Moved conditional code around where possible so that
we could always use Q_UNLIKELY, instead of having to
revert to Q_LIKELY here and there.

In QSystemTrayIcon::setVisible(), as a drive-by, I
swapped the evaluation order of an &&-expression
(newly wrapped in Q_UNLIKELY) to be more readable
and more efficient (cheaper check first) at the same
time.

Change-Id: I3564c5a5deacba49d67d3989fb0b53e680c57fcb
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

33 files changed, 99 insertions, 100 deletions

diff --git a/src/widgets/dialogs/qdialog.cpp b/src/widgets/dialogs/qdialog.cpp
index 5124960ab4..4ba26a90f7 100644
--- a/src/widgets/dialogs/qdialog.cpp
+++ b/src/widgets/dialogs/qdialog.cpp
@@ -516,7 +516,7 @@ int QDialog::exec()
 {
     Q_D(QDialog);
 
-    if (d->eventLoop) {
+    if (Q_UNLIKELY(d->eventLoop)) {
         qWarning("QDialog::exec: Recursive call detected");
         return -1;
     }
diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index cd26a6759f..11067544c3 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -976,7 +976,7 @@ void QFileDialog::setDirectoryUrl(const QUrl &directory)
         d->setDirectory_sys(directory);
     else if (directory.isLocalFile())
         setDirectory(directory.toLocalFile());
-    else if (d->usingWidgets())
+    else if (Q_UNLIKELY(d->usingWidgets()))
         qWarning("Non-native QFileDialog supports only local files");
 }
 
diff --git a/src/widgets/dialogs/qprogressdialog.cpp b/src/widgets/dialogs/qprogressdialog.cpp
index bbb251c8b2..619d0051ea 100644
--- a/src/widgets/dialogs/qprogressdialog.cpp
+++ b/src/widgets/dialogs/qprogressdialog.cpp
@@ -353,7 +353,7 @@ void QProgressDialog::setLabel(QLabel *label)
 {
     Q_D(QProgressDialog);
     if (label == d->label) {
-        if (label)
+        if (Q_UNLIKELY(label))
             qWarning("QProgressDialog::setLabel: Attempt to set the same label again");
         return;
     }
@@ -402,7 +402,7 @@ void QProgressDialog::setCancelButton(QPushButton *cancelButton)
 {
     Q_D(QProgressDialog);
     if (d->cancel == cancelButton) {
-        if (cancelButton)
+        if (Q_UNLIKELY(cancelButton))
             qWarning("QProgressDialog::setCancelButton: Attempt to set the same button again");
         return;
     }
@@ -465,16 +465,16 @@ void QProgressDialogPrivate::setCancelButtonText(const QString &cancelButtonText
 void QProgressDialog::setBar(QProgressBar *bar)
 {
     Q_D(QProgressDialog);
-    if (!bar) {
+    if (Q_UNLIKELY(!bar)) {
         qWarning("QProgressDialog::setBar: Cannot set a null progress bar");
         return;
     }
 #ifndef QT_NO_DEBUG
-    if (value() > 0)
+    if (Q_UNLIKELY(value() > 0))
         qWarning("QProgressDialog::setBar: Cannot set a new progress bar "
                   "while the old one is active");
 #endif
-    if (bar == d->bar) {
+    if (Q_UNLIKELY(bar == d->bar)) {
         qWarning("QProgressDialog::setBar: Attempt to set the same progress bar again");
         return;
     }
diff --git a/src/widgets/dialogs/qwizard.cpp b/src/widgets/dialogs/qwizard.cpp
index 996e5819ff..c050b5b097 100644
--- a/src/widgets/dialogs/qwizard.cpp
+++ b/src/widgets/dialogs/qwizard.cpp
@@ -799,7 +799,7 @@ void QWizardPrivate::addField(const QWizardField &field)
     QWizardField myField = field;
     myField.resolve(defaultPropertyTable);
 
-    if (fieldIndexMap.contains(myField.name)) {
+    if (Q_UNLIKELY(fieldIndexMap.contains(myField.name))) {
         qWarning("QWizardPage::addField: Duplicate field '%ls'", qUtf16Printable(myField.name));
         return;
     }
@@ -2256,17 +2256,17 @@ void QWizard::setPage(int theid, QWizardPage *page)
 {
     Q_D(QWizard);
 
-    if (!page) {
+    if (Q_UNLIKELY(!page)) {
         qWarning("QWizard::setPage: Cannot insert null page");
         return;
     }
 
-    if (theid == -1) {
+    if (Q_UNLIKELY(theid == -1)) {
         qWarning("QWizard::setPage: Cannot insert page with ID -1");
         return;
     }
 
-    if (d->pageMap.contains(theid)) {
+    if (Q_UNLIKELY(d->pageMap.contains(theid))) {
         qWarning("QWizard::setPage: Page with duplicate ID %d ignored", theid);
         return;
     }
@@ -2450,7 +2450,7 @@ void QWizard::setStartId(int theid)
         return;
     }
 
-    if (!d->pageMap.contains(newStart)) {
+    if (Q_UNLIKELY(!d->pageMap.contains(newStart))) {
         qWarning("QWizard::setStartId: Invalid page ID %d", newStart);
         return;
     }
@@ -2508,15 +2508,15 @@ void QWizard::setField(const QString &name, const QVariant &value)
     Q_D(QWizard);
 
     int index = d->fieldIndexMap.value(name, -1);
-    if (index != -1) {
-        const QWizardField &field = d->fields.at(index);
-        if (!field.object->setProperty(field.property, value))
-            qWarning("QWizard::setField: Couldn't write to property '%s'",
-                     field.property.constData());
+    if (Q_UNLIKELY(index == -1)) {
+        qWarning("QWizard::setField: No such field '%ls'", qUtf16Printable(name));
         return;
     }
 
-    qWarning("QWizard::setField: No such field '%ls'", qUtf16Printable(name));
+    const QWizardField &field = d->fields.at(index);
+    if (Q_UNLIKELY(!field.object->setProperty(field.property, value)))
+        qWarning("QWizard::setField: Couldn't write to property '%s'",
+                 field.property.constData());
 }
 
 /*!
@@ -2531,13 +2531,13 @@ QVariant QWizard::field(const QString &name) const
     Q_D(const QWizard);
 
     int index = d->fieldIndexMap.value(name, -1);
-    if (index != -1) {
-        const QWizardField &field = d->fields.at(index);
-        return field.object->property(field.property);
+    if (Q_UNLIKELY(index == -1)) {
+        qWarning("QWizard::field: No such field '%ls'", qUtf16Printable(name));
+        return QVariant();
     }
 
-    qWarning("QWizard::field: No such field '%ls'", qUtf16Printable(name));
-    return QVariant();
+    const QWizardField &field = d->fields.at(index);
+    return field.object->property(field.property);
 }
 
 /*!
@@ -2763,7 +2763,7 @@ void QWizard::setButtonLayout(const QList<WizardButton> &layout)
         // O(n^2), but n is very small
         for (int j = 0; j < i; ++j) {
             WizardButton button2 = layout.at(j);
-            if (button2 == button1) {
+            if (Q_UNLIKELY(button2 == button1)) {
                 qWarning("QWizard::setButtonLayout: Duplicate button in layout");
                 return;
             }
@@ -3140,11 +3140,11 @@ void QWizard::next()
     if (validateCurrentPage()) {
         int next = nextId();
         if (next != -1) {
-            if (d->history.contains(next)) {
+            if (Q_UNLIKELY(d->history.contains(next))) {
                 qWarning("QWizard::next: Page %d already met", next);
                 return;
             }
-            if (!d->pageMap.contains(next)) {
+            if (Q_UNLIKELY(!d->pageMap.contains(next))) {
                 qWarning("QWizard::next: No such page %d", next);
                 return;
             }
diff --git a/src/widgets/util/qcolormap.cpp b/src/widgets/util/qcolormap.cpp
index fc4d511384..4bcf1501d2 100644
--- a/src/widgets/util/qcolormap.cpp
+++ b/src/widgets/util/qcolormap.cpp
@@ -58,7 +58,7 @@ static QColormapPrivate *screenMap = 0;
 void QColormap::initialize()
 {
     screenMap = new QColormapPrivate;
-    if (!QGuiApplication::primaryScreen()) {
+    if (Q_UNLIKELY(!QGuiApplication::primaryScreen())) {
         qWarning("no screens available, assuming 24-bit color");
         screenMap->depth = 24;
         screenMap->mode = QColormap::Direct;
diff --git a/src/widgets/util/qcompleter.cpp b/src/widgets/util/qcompleter.cpp
index ba56f004b7..55ceeca919 100644
--- a/src/widgets/util/qcompleter.cpp
+++ b/src/widgets/util/qcompleter.cpp
@@ -1144,9 +1144,9 @@ void QCompleter::setFilterMode(Qt::MatchFlags filterMode)
     if (d->filterMode == filterMode)
         return;
 
-    if (filterMode != Qt::MatchStartsWith
-            && filterMode != Qt::MatchContains
-            && filterMode != Qt::MatchEndsWith) {
+    if (Q_UNLIKELY(filterMode != Qt::MatchStartsWith &&
+                   filterMode != Qt::MatchContains &&
+                   filterMode != Qt::MatchEndsWith)) {
         qWarning("Unhandled QCompleter::filterMode flag is used.");
         return;
     }
@@ -1641,7 +1641,7 @@ int QCompleter::maxVisibleItems() const
 void QCompleter::setMaxVisibleItems(int maxItems)
 {
     Q_D(QCompleter);
-    if (maxItems < 0) {
+    if (Q_UNLIKELY(maxItems < 0)) {
         qWarning("QCompleter::setMaxVisibleItems: "
                  "Invalid max visible items (%d) must be >= 0", maxItems);
         return;
diff --git a/src/widgets/util/qscroller.cpp b/src/widgets/util/qscroller.cpp
index 0065ccf6b3..c540c3cdf0 100644
--- a/src/widgets/util/qscroller.cpp
+++ b/src/widgets/util/qscroller.cpp
@@ -159,8 +159,8 @@ static qreal differentialForProgress(const QEasingCurve &curve, qreal pos)
 
 static qreal progressForValue(const QEasingCurve &curve, qreal value)
 {
-    if (curve.type() >= QEasingCurve::InElastic &&
-        curve.type() < QEasingCurve::Custom) {
+    if (Q_UNLIKELY(curve.type() >= QEasingCurve::InElastic &&
+                   curve.type() < QEasingCurve::Custom)) {
         qWarning("progressForValue(): QEasingCurves of type %d do not have an inverse, since they are not injective.", curve.type());
         return value;
     }
diff --git a/src/widgets/util/qsystemtrayicon.cpp b/src/widgets/util/qsystemtrayicon.cpp
index d22791048f..20f5c95ae9 100644
--- a/src/widgets/util/qsystemtrayicon.cpp
+++ b/src/widgets/util/qsystemtrayicon.cpp
@@ -264,7 +264,7 @@ void QSystemTrayIcon::setVisible(bool visible)
     Q_D(QSystemTrayIcon);
     if (visible == d->visible)
         return;
-    if (d->icon.isNull() && visible)
+    if (Q_UNLIKELY(visible && d->icon.isNull()))
         qWarning("QSystemTrayIcon::setVisible: No Icon set");
     d->visible = visible;
     if (d->visible)
diff --git a/src/widgets/util/qundostack.cpp b/src/widgets/util/qundostack.cpp
index 0272870537..35d8c10578 100644
--- a/src/widgets/util/qundostack.cpp
+++ b/src/widgets/util/qundostack.cpp
@@ -633,7 +633,7 @@ void QUndoStack::push(QUndoCommand *cmd)
 void QUndoStack::setClean()
 {
     Q_D(QUndoStack);
-    if (!d->macro_stack.isEmpty()) {
+    if (Q_UNLIKELY(!d->macro_stack.isEmpty())) {
         qWarning("QUndoStack::setClean(): cannot set clean in the middle of a macro");
         return;
     }
@@ -688,7 +688,7 @@ void QUndoStack::undo()
     if (d->index == 0)
         return;
 
-    if (!d->macro_stack.isEmpty()) {
+    if (Q_UNLIKELY(!d->macro_stack.isEmpty())) {
         qWarning("QUndoStack::undo(): cannot undo in the middle of a macro");
         return;
     }
@@ -714,7 +714,7 @@ void QUndoStack::redo()
     if (d->index == d->command_list.size())
         return;
 
-    if (!d->macro_stack.isEmpty()) {
+    if (Q_UNLIKELY(!d->macro_stack.isEmpty())) {
         qWarning("QUndoStack::redo(): cannot redo in the middle of a macro");
         return;
     }
@@ -761,7 +761,7 @@ int QUndoStack::index() const
 void QUndoStack::setIndex(int idx)
 {
     Q_D(QUndoStack);
-    if (!d->macro_stack.isEmpty()) {
+    if (Q_UNLIKELY(!d->macro_stack.isEmpty())) {
         qWarning("QUndoStack::setIndex(): cannot set index in the middle of a macro");
         return;
     }
@@ -981,7 +981,7 @@ void QUndoStack::beginMacro(const QString &text)
 void QUndoStack::endMacro()
 {
     Q_D(QUndoStack);
-    if (d->macro_stack.isEmpty()) {
+    if (Q_UNLIKELY(d->macro_stack.isEmpty())) {
         qWarning("QUndoStack::endMacro(): no matching beginMacro()");
         return;
     }
@@ -1049,7 +1049,7 @@ void QUndoStack::setUndoLimit(int limit)
 {
     Q_D(QUndoStack);
 
-    if (!d->command_list.isEmpty()) {
+    if (Q_UNLIKELY(!d->command_list.isEmpty())) {
         qWarning("QUndoStack::setUndoLimit(): an undo limit can only be set when the stack is empty");
         return;
     }
diff --git a/src/widgets/widgets/qabstractscrollarea.cpp b/src/widgets/widgets/qabstractscrollarea.cpp
index 65d06eafc5..ed6b039c7c 100644
--- a/src/widgets/widgets/qabstractscrollarea.cpp
+++ b/src/widgets/widgets/qabstractscrollarea.cpp
@@ -705,7 +705,7 @@ QScrollBar *QAbstractScrollArea::verticalScrollBar() const
 void QAbstractScrollArea::setVerticalScrollBar(QScrollBar *scrollBar)
 {
     Q_D(QAbstractScrollArea);
-    if (!scrollBar) {
+    if (Q_UNLIKELY(!scrollBar)) {
         qWarning("QAbstractScrollArea::setVerticalScrollBar: Cannot set a null scroll bar");
         return;
     }
@@ -766,7 +766,7 @@ QScrollBar *QAbstractScrollArea::horizontalScrollBar() const
 void QAbstractScrollArea::setHorizontalScrollBar(QScrollBar *scrollBar)
 {
     Q_D(QAbstractScrollArea);
-    if (!scrollBar) {
+    if (Q_UNLIKELY(!scrollBar)) {
         qWarning("QAbstractScrollArea::setHorizontalScrollBar: Cannot set a null scroll bar");
         return;
     }
diff --git a/src/widgets/widgets/qabstractspinbox.cpp b/src/widgets/widgets/qabstractspinbox.cpp
index ba4bbe40a8..40c148f4c6 100644
--- a/src/widgets/widgets/qabstractspinbox.cpp
+++ b/src/widgets/widgets/qabstractspinbox.cpp
@@ -1931,7 +1931,7 @@ void QSpinBoxValidator::fixup(QString &input) const
 QVariant operator+(const QVariant &arg1, const QVariant &arg2)
 {
     QVariant ret;
-    if (arg1.type() != arg2.type())
+    if (Q_UNLIKELY(arg1.type() != arg2.type()))
         qWarning("QAbstractSpinBox: Internal error: Different types (%s vs %s) (%s:%d)",
                  arg1.typeName(), arg2.typeName(), __FILE__, __LINE__);
     switch (arg1.type()) {
@@ -1970,7 +1970,7 @@ QVariant operator+(const QVariant &arg1, const QVariant &arg2)
 QVariant operator-(const QVariant &arg1, const QVariant &arg2)
 {
     QVariant ret;
-    if (arg1.type() != arg2.type())
+    if (Q_UNLIKELY(arg1.type() != arg2.type()))
         qWarning("QAbstractSpinBox: Internal error: Different types (%s vs %s) (%s:%d)",
                  arg1.typeName(), arg2.typeName(), __FILE__, __LINE__);
     switch (arg1.type()) {
diff --git a/src/widgets/widgets/qcalendarwidget.cpp b/src/widgets/widgets/qcalendarwidget.cpp
index 5e6db46a63..eb216b1ad0 100644
--- a/src/widgets/widgets/qcalendarwidget.cpp
+++ b/src/widgets/widgets/qcalendarwidget.cpp
@@ -2917,7 +2917,7 @@ void QCalendarWidget::setDateEditAcceptDelay(int delay)
 */
 void QCalendarWidget::updateCell(const QDate &date)
 {
-    if (!date.isValid()) {
+    if (Q_UNLIKELY(!date.isValid())) {
         qWarning("QCalendarWidget::updateCell: Invalid date");
         return;
     }
diff --git a/src/widgets/widgets/qcombobox.cpp b/src/widgets/widgets/qcombobox.cpp
index deffad432f..401f365426 100644
--- a/src/widgets/widgets/qcombobox.cpp
+++ b/src/widgets/widgets/qcombobox.cpp
@@ -1360,7 +1360,7 @@ int QComboBox::maxVisibleItems() const
 void QComboBox::setMaxVisibleItems(int maxItems)
 {
     Q_D(QComboBox);
-    if (maxItems < 0) {
+    if (Q_UNLIKELY(maxItems < 0)) {
         qWarning("QComboBox::setMaxVisibleItems: "
                  "Invalid max visible items (%d) must be >= 0", maxItems);
         return;
@@ -1395,7 +1395,7 @@ int QComboBox::count() const
 void QComboBox::setMaxCount(int max)
 {
     Q_D(QComboBox);
-    if (max < 0) {
+    if (Q_UNLIKELY(max < 0)) {
         qWarning("QComboBox::setMaxCount: Invalid count (%d) must be >= 0", max);
         return;
     }
@@ -1448,7 +1448,7 @@ void QComboBox::setAutoCompletion(bool enable)
     Q_D(QComboBox);
 
 #ifdef QT_KEYPAD_NAVIGATION
-    if (QApplication::keypadNavigationEnabled() && !enable && isEditable())
+    if (Q_UNLIKELY(QApplication::keypadNavigationEnabled() && !enable && isEditable()))
         qWarning("QComboBox::setAutoCompletion: auto completion is mandatory when combo box editable");
 #endif
 
@@ -1758,7 +1758,7 @@ void QComboBox::setEditable(bool editable)
 void QComboBox::setLineEdit(QLineEdit *edit)
 {
     Q_D(QComboBox);
-    if (!edit) {
+    if (Q_UNLIKELY(!edit)) {
         qWarning("QComboBox::setLineEdit: cannot set a 0 line edit");
         return;
     }
@@ -1917,7 +1917,7 @@ QAbstractItemDelegate *QComboBox::itemDelegate() const
 */
 void QComboBox::setItemDelegate(QAbstractItemDelegate *delegate)
 {
-    if (!delegate) {
+    if (Q_UNLIKELY(!delegate)) {
         qWarning("QComboBox::setItemDelegate: cannot set a 0 delegate");
         return;
     }
@@ -1949,7 +1949,7 @@ void QComboBox::setModel(QAbstractItemModel *model)
 {
     Q_D(QComboBox);
 
-    if (!model) {
+    if (Q_UNLIKELY(!model)) {
         qWarning("QComboBox::setModel: cannot set a 0 model");
         return;
     }
@@ -2395,7 +2395,7 @@ QAbstractItemView *QComboBox::view() const
 void QComboBox::setView(QAbstractItemView *itemView)
 {
     Q_D(QComboBox);
-    if (!itemView) {
+    if (Q_UNLIKELY(!itemView)) {
         qWarning("QComboBox::setView: cannot set a 0 view");
         return;
     }
diff --git a/src/widgets/widgets/qdatetimeedit.cpp b/src/widgets/widgets/qdatetimeedit.cpp
index 42987df3ec..bff1ff6c67 100644
--- a/src/widgets/widgets/qdatetimeedit.cpp
+++ b/src/widgets/widgets/qdatetimeedit.cpp
@@ -760,17 +760,17 @@ QCalendarWidget *QDateTimeEdit::calendarWidget() const
 void QDateTimeEdit::setCalendarWidget(QCalendarWidget *calendarWidget)
 {
     Q_D(QDateTimeEdit);
-    if (!calendarWidget) {
+    if (Q_UNLIKELY(!calendarWidget)) {
         qWarning("QDateTimeEdit::setCalendarWidget: Cannot set a null calendar widget");
         return;
     }
 
-    if (!d->calendarPopup) {
+    if (Q_UNLIKELY(!d->calendarPopup)) {
         qWarning("QDateTimeEdit::setCalendarWidget: calendarPopup is set to false");
         return;
     }
 
-    if (!(d->display & QDateTimeParser::DateSectionMask)) {
+    if (Q_UNLIKELY(!(d->display & QDateTimeParser::DateSectionMask))) {
         qWarning("QDateTimeEdit::setCalendarWidget: no date sections specified");
         return;
     }
@@ -1864,7 +1864,7 @@ void QDateTimeEditPrivate::clearSection(int index)
     const QSignalBlocker blocker(edit);
     QString t = edit->text();
     const int pos = sectionPos(index);
-    if (pos == -1) {
+    if (Q_UNLIKELY(pos == -1)) {
         qWarning("QDateTimeEdit: Internal error (%s:%d)", __FILE__, __LINE__);
         return;
     }
diff --git a/src/widgets/widgets/qdialogbuttonbox.cpp b/src/widgets/widgets/qdialogbuttonbox.cpp
index 5b6bfb3b3c..e262f2db22 100644
--- a/src/widgets/widgets/qdialogbuttonbox.cpp
+++ b/src/widgets/widgets/qdialogbuttonbox.cpp
@@ -405,11 +405,10 @@ QPushButton *QDialogButtonBoxPrivate::createButton(QDialogButtonBox::StandardBut
         button->setStyle(style);
     standardButtonHash.insert(button, sbutton);
     QPlatformDialogHelper::ButtonRole role = QPlatformDialogHelper::buttonRole(static_cast<QPlatformDialogHelper::StandardButton>(sbutton));
-    if (role != QPlatformDialogHelper::InvalidRole) {
-        addButton(button, static_cast<QDialogButtonBox::ButtonRole>(role), doLayout);
-    } else {
+    if (Q_UNLIKELY(role == QPlatformDialogHelper::InvalidRole))
         qWarning("QDialogButtonBox::createButton: Invalid ButtonRole, button not added");
-    }
+    else
+        addButton(button, static_cast<QDialogButtonBox::ButtonRole>(role), doLayout);
 
 #ifdef Q_DEAD_CODE_FROM_QT4_MAC
     // Since mnemonics is off by default on Mac, we add a Cmd-D
@@ -753,7 +752,7 @@ void QDialogButtonBox::removeButton(QAbstractButton *button)
 void QDialogButtonBox::addButton(QAbstractButton *button, ButtonRole role)
 {
     Q_D(QDialogButtonBox);
-    if (role <= InvalidRole || role >= NRoles) {
+    if (Q_UNLIKELY(role <= InvalidRole || role >= NRoles)) {
         qWarning("QDialogButtonBox::addButton: Invalid ButtonRole, button not added");
         return;
     }
@@ -772,7 +771,7 @@ void QDialogButtonBox::addButton(QAbstractButton *button, ButtonRole role)
 QPushButton *QDialogButtonBox::addButton(const QString &text, ButtonRole role)
 {
     Q_D(QDialogButtonBox);
-    if (role <= InvalidRole || role >= NRoles) {
+    if (Q_UNLIKELY(role <= InvalidRole || role >= NRoles)) {
         qWarning("QDialogButtonBox::addButton: Invalid ButtonRole, button not added");
         return 0;
     }
diff --git a/src/widgets/widgets/qdockarealayout.cpp b/src/widgets/widgets/qdockarealayout.cpp
index 6c38043e01..b12aa65dcd 100644
--- a/src/widgets/widgets/qdockarealayout.cpp
+++ b/src/widgets/widgets/qdockarealayout.cpp
@@ -1802,7 +1802,7 @@ void QDockAreaLayoutInfo::saveState(QDataStream &stream) const
             stream << (uchar) WidgetMarker;
             QWidget *w = item.widgetItem->widget();
             QString name = w->objectName();
-            if (name.isEmpty()) {
+            if (Q_UNLIKELY(name.isEmpty())) {
                 qWarning("QMainWindow::saveState(): 'objectName' not set for QDockWidget %p '%ls;",
                          w, qUtf16Printable(w->windowTitle()));
             }
@@ -3109,7 +3109,7 @@ void QDockAreaLayout::tabifyDockWidget(QDockWidget *first, QDockWidget *second)
 void QDockAreaLayout::resizeDocks(const QList<QDockWidget *> &docks,
                                   const QList<int> &sizes, Qt::Orientation o)
 {
-    if (docks.count() != sizes.count()) {
+    if (Q_UNLIKELY(docks.count() != sizes.count())) {
         qWarning("QMainWidget::resizeDocks: size of the lists are not the same");
         return;
     }
@@ -3117,12 +3117,12 @@ void QDockAreaLayout::resizeDocks(const QList<QDockWidget *> &docks,
     fallbackToSizeHints = false;
     for (int i = 0; i < count; ++i) {
         QList<int> path = indexOf(docks[i]);
-        if (path.isEmpty()) {
+        if (Q_UNLIKELY(path.isEmpty())) {
             qWarning("QMainWidget::resizeDocks: one QDockWidget is not part of the layout");
             continue;
         }
         int size = sizes[i];
-        if (size <= 0) {
+        if (Q_UNLIKELY(size <= 0)) {
             qWarning("QMainWidget::resizeDocks: all sizes need to be larger than 0");
             size = 1;
         }
diff --git a/src/widgets/widgets/qlcdnumber.cpp b/src/widgets/widgets/qlcdnumber.cpp
index d17e3e2470..b9c209ed3b 100644
--- a/src/widgets/widgets/qlcdnumber.cpp
+++ b/src/widgets/widgets/qlcdnumber.cpp
@@ -402,12 +402,12 @@ QLCDNumber::~QLCDNumber()
 void QLCDNumber::setDigitCount(int numDigits)
 {
     Q_D(QLCDNumber);
-    if (numDigits > 99) {
+    if (Q_UNLIKELY(numDigits > 99)) {
         qWarning("QLCDNumber::setNumDigits: (%s) Max 99 digits allowed",
                  objectName().toLocal8Bit().constData());
         numDigits = 99;
     }
-    if (numDigits < 0) {
+    if (Q_UNLIKELY(numDigits < 0)) {
         qWarning("QLCDNumber::setNumDigits: (%s) Min 0 digits allowed",
                  objectName().toLocal8Bit().constData());
         numDigits = 0;
diff --git a/src/widgets/widgets/qlineedit.cpp b/src/widgets/widgets/qlineedit.cpp
index 6b32665065..b8283a0818 100644
--- a/src/widgets/widgets/qlineedit.cpp
+++ b/src/widgets/widgets/qlineedit.cpp
@@ -982,7 +982,7 @@ int QLineEdit::selectionStart() const
 void QLineEdit::setSelection(int start, int length)
 {
     Q_D(QLineEdit);
-    if (start < 0 || start > (int)d->control->end()) {
+    if (Q_UNLIKELY(start < 0 || start > (int)d->control->end())) {
         qWarning("QLineEdit::setSelection: Invalid start position (%d)", start);
         return;
     }
diff --git a/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm b/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
index 7dad6604b9..7bd539033a 100644
--- a/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
+++ b/src/widgets/widgets/qmaccocoaviewcontainer_mac.mm
@@ -93,7 +93,7 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
-    if (!function)
+    if (Q_UNLIKELY(!function))
          qWarning() << "Qt could not resolve function" << functionName
                     << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
     return function;
diff --git a/src/widgets/widgets/qmacnativewidget_mac.mm b/src/widgets/widgets/qmacnativewidget_mac.mm
index f855777837..729aa9aba0 100644
--- a/src/widgets/widgets/qmacnativewidget_mac.mm
+++ b/src/widgets/widgets/qmacnativewidget_mac.mm
@@ -82,7 +82,7 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
-    if (!function)
+    if (Q_UNLIKELY(!function))
          qWarning() << "Qt could not resolve function" << functionName
                     << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
     return function;
diff --git a/src/widgets/widgets/qmainwindow.cpp b/src/widgets/widgets/qmainwindow.cpp
index ff4bb3cc98..2fbd83ef54 100644
--- a/src/widgets/widgets/qmainwindow.cpp
+++ b/src/widgets/widgets/qmainwindow.cpp
@@ -693,7 +693,7 @@ void QMainWindow::setCorner(Qt::Corner corner, Qt::DockWidgetArea area)
         valid = (area == Qt::BottomDockWidgetArea || area == Qt::RightDockWidgetArea);
         break;
     }
-    if (!valid)
+    if (Q_UNLIKELY(!valid))
         qWarning("QMainWindow::setCorner(): 'area' is not valid for 'corner'");
     else
         d_func()->layout->setCorner(corner, area);
diff --git a/src/widgets/widgets/qmdiarea.cpp b/src/widgets/widgets/qmdiarea.cpp
index 1864b42a80..55ae866358 100644
--- a/src/widgets/widgets/qmdiarea.cpp
+++ b/src/widgets/widgets/qmdiarea.cpp
@@ -179,7 +179,7 @@ using namespace QMdi;
 // Asserts in debug mode, gives warning otherwise.
 static bool sanityCheck(const QMdiSubWindow * const child, const char *where)
 {
-    if (!child) {
+    if (Q_UNLIKELY(!child)) {
         const char error[] = "null pointer";
         Q_ASSERT_X(false, where, error);
         qWarning("%s:%s", where, error);
@@ -190,13 +190,13 @@ static bool sanityCheck(const QMdiSubWindow * const child, const char *where)
 
 static bool sanityCheck(const QList<QWidget *> &widgets, const int index, const char *where)
 {
-    if (index < 0 || index >= widgets.size()) {
+    if (Q_UNLIKELY(index < 0 || index >= widgets.size())) {
         const char error[] = "index out of range";
         Q_ASSERT_X(false, where, error);
         qWarning("%s:%s", where, error);
         return false;
     }
-    if (!widgets.at(index)) {
+    if (Q_UNLIKELY(!widgets.at(index))) {
         const char error[] = "null pointer";
         Q_ASSERT_X(false, where, error);
         qWarning("%s:%s", where, error);
@@ -1831,12 +1831,12 @@ void QMdiArea::setActiveSubWindow(QMdiSubWindow *window)
         return;
     }
 
-    if (d->childWindows.isEmpty()) {
+    if (Q_UNLIKELY(d->childWindows.isEmpty())) {
         qWarning("QMdiArea::setActiveSubWindow: workspace is empty");
         return;
     }
 
-    if (d->childWindows.indexOf(window) == -1) {
+    if (Q_UNLIKELY(d->childWindows.indexOf(window) == -1)) {
         qWarning("QMdiArea::setActiveSubWindow: window is not inside workspace");
         return;
     }
@@ -1960,7 +1960,7 @@ void QMdiArea::activatePreviousSubWindow()
 */
 QMdiSubWindow *QMdiArea::addSubWindow(QWidget *widget, Qt::WindowFlags windowFlags)
 {
-    if (!widget) {
+    if (Q_UNLIKELY(!widget)) {
         qWarning("QMdiArea::addSubWindow: null pointer to widget");
         return 0;
     }
@@ -1972,7 +1972,7 @@ QMdiSubWindow *QMdiArea::addSubWindow(QWidget *widget, Qt::WindowFlags windowFla
 
     // Widget is already a QMdiSubWindow
     if (child) {
-        if (d->childWindows.indexOf(child) != -1) {
+        if (Q_UNLIKELY(d->childWindows.indexOf(child) != -1)) {
             qWarning("QMdiArea::addSubWindow: window is already added");
             return child;
         }
@@ -2003,7 +2003,7 @@ QMdiSubWindow *QMdiArea::addSubWindow(QWidget *widget, Qt::WindowFlags windowFla
 */
 void QMdiArea::removeSubWindow(QWidget *widget)
 {
-    if (!widget) {
+    if (Q_UNLIKELY(!widget)) {
         qWarning("QMdiArea::removeSubWindow: null pointer to widget");
         return;
     }
@@ -2014,7 +2014,7 @@ void QMdiArea::removeSubWindow(QWidget *widget)
 
     if (QMdiSubWindow *child = qobject_cast<QMdiSubWindow *>(widget)) {
         int index = d->childWindows.indexOf(child);
-        if (index == -1) {
+        if (Q_UNLIKELY(index == -1)) {
             qWarning("QMdiArea::removeSubWindow: window is not inside workspace");
             return;
         }
@@ -2038,7 +2038,7 @@ void QMdiArea::removeSubWindow(QWidget *widget)
         }
     }
 
-    if (!found)
+    if (Q_UNLIKELY(!found))
         qWarning("QMdiArea::removeSubWindow: widget is not child of any window inside QMdiArea");
 }
 
diff --git a/src/widgets/widgets/qmdisubwindow.cpp b/src/widgets/widgets/qmdisubwindow.cpp
index be6cb7c54c..0f38eee6cd 100644
--- a/src/widgets/widgets/qmdisubwindow.cpp
+++ b/src/widgets/widgets/qmdisubwindow.cpp
@@ -2309,7 +2309,7 @@ void QMdiSubWindow::setWidget(QWidget *widget)
         return;
     }
 
-    if (widget == d->baseWidget) {
+    if (Q_UNLIKELY(widget == d->baseWidget)) {
         qWarning("QMdiSubWindow::setWidget: widget is already set");
         return;
     }
@@ -2507,7 +2507,7 @@ void QMdiSubWindow::setKeyboardPageStep(int step)
 void QMdiSubWindow::setSystemMenu(QMenu *systemMenu)
 {
     Q_D(QMdiSubWindow);
-    if (systemMenu && systemMenu == d->systemMenu) {
+    if (Q_UNLIKELY(systemMenu && systemMenu == d->systemMenu)) {
         qWarning("QMdiSubWindow::setSystemMenu: system menu is already set");
         return;
     }
diff --git a/src/widgets/widgets/qmenu_mac.mm b/src/widgets/widgets/qmenu_mac.mm
index 9278099e18..58dee37bd9 100644
--- a/src/widgets/widgets/qmenu_mac.mm
+++ b/src/widgets/widgets/qmenu_mac.mm
@@ -55,7 +55,7 @@ inline QPlatformNativeInterface::NativeResourceForIntegrationFunction resolvePla
     QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
     QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
         nativeInterface->nativeResourceFunctionForIntegration(functionName);
-    if (!function)
+    if (Q_UNLIKELY(!function))
          qWarning() << "Qt could not resolve function" << functionName
                     << "from QGuiApplication::platformNativeInterface()->nativeResourceFunctionForIntegration()";
     return function;
diff --git a/src/widgets/widgets/qplaintextedit.cpp b/src/widgets/widgets/qplaintextedit.cpp
index 91788a3383..5e4e348e3b 100644
--- a/src/widgets/widgets/qplaintextedit.cpp
+++ b/src/widgets/widgets/qplaintextedit.cpp
@@ -1291,7 +1291,7 @@ void QPlainTextEdit::setDocument(QTextDocument *document)
         document->setDocumentLayout(documentLayout);
     } else {
         documentLayout = qobject_cast<QPlainTextDocumentLayout*>(document->documentLayout());
-        if (!documentLayout) {
+        if (Q_UNLIKELY(!documentLayout)) {
             qWarning("QPlainTextEdit::setDocument: Document set does not support QPlainTextDocumentLayout");
             return;
         }
diff --git a/src/widgets/widgets/qspinbox.cpp b/src/widgets/widgets/qspinbox.cpp
index 457e2e1e4c..13076ad870 100644
--- a/src/widgets/widgets/qspinbox.cpp
+++ b/src/widgets/widgets/qspinbox.cpp
@@ -438,7 +438,7 @@ void QSpinBox::setDisplayIntegerBase(int base)
 {
     Q_D(QSpinBox);
     // Falls back to base 10 on invalid bases (like QString)
-    if (base < 2 || base > 36) {
+    if (Q_UNLIKELY(base < 2 || base > 36)) {
         qWarning("QSpinBox::setDisplayIntegerBase: Invalid base (%d)", base);
         base = 10;
     }
diff --git a/src/widgets/widgets/qsplitter.cpp b/src/widgets/widgets/qsplitter.cpp
index c2081c15f8..9162ba3c12 100644
--- a/src/widgets/widgets/qsplitter.cpp
+++ b/src/widgets/widgets/qsplitter.cpp
@@ -1058,7 +1058,7 @@ void QSplitter::setCollapsible(int index, bool collapse)
 {
     Q_D(QSplitter);
 
-    if (index < 0 || index >= d->list.size()) {
+    if (Q_UNLIKELY(index < 0 || index >= d->list.size())) {
         qWarning("QSplitter::setCollapsible: Index %d out of range", index);
         return;
     }
@@ -1071,7 +1071,7 @@ void QSplitter::setCollapsible(int index, bool collapse)
 bool QSplitter::isCollapsible(int index) const
 {
     Q_D(const QSplitter);
-    if (index < 0 || index >= d->list.size()) {
+    if (Q_UNLIKELY(index < 0 || index >= d->list.size())) {
         qWarning("QSplitter::isCollapsible: Index %d out of range", index);
         return false;
     }
@@ -1215,7 +1215,7 @@ void QSplitter::childEvent(QChildEvent *c)
 {
     Q_D(QSplitter);
     if (!c->child()->isWidgetType()) {
-        if (c->type() == QEvent::ChildAdded && qobject_cast<QLayout *>(c->child()))
+        if (Q_UNLIKELY(c->type() == QEvent::ChildAdded && qobject_cast<QLayout *>(c->child())))
             qWarning("Adding a QLayout to a QSplitter is not supported.");
         return;
     }
diff --git a/src/widgets/widgets/qstackedwidget.cpp b/src/widgets/widgets/qstackedwidget.cpp
index 19a2edf0f2..8a2eff4e39 100644
--- a/src/widgets/widgets/qstackedwidget.cpp
+++ b/src/widgets/widgets/qstackedwidget.cpp
@@ -237,7 +237,7 @@ QWidget *QStackedWidget::currentWidget() const
 void QStackedWidget::setCurrentWidget(QWidget *widget)
 {
     Q_D(QStackedWidget);
-    if (d->layout->indexOf(widget) == -1) {
+    if (Q_UNLIKELY(d->layout->indexOf(widget) == -1)) {
         qWarning("QStackedWidget::setCurrentWidget: widget %p not contained in stack", widget);
         return;
     }
diff --git a/src/widgets/widgets/qstatusbar.cpp b/src/widgets/widgets/qstatusbar.cpp
index 19361fc793..2e8ca8510b 100644
--- a/src/widgets/widgets/qstatusbar.cpp
+++ b/src/widgets/widgets/qstatusbar.cpp
@@ -296,7 +296,7 @@ int QStatusBar::insertWidget(int index, QWidget *widget, int stretch)
     QStatusBarPrivate::SBItem* item = new QStatusBarPrivate::SBItem(widget, stretch, false);
 
     int idx = d->indexToLastNonPermanentWidget();
-    if (index < 0 || index > d->items.size() || (idx >= 0 && index > idx + 1)) {
+    if (Q_UNLIKELY(index < 0 || index > d->items.size() || (idx >= 0 && index > idx + 1))) {
         qWarning("QStatusBar::insertWidget: Index out of range (%d), appending widget", index);
         index = idx + 1;
     }
@@ -361,7 +361,7 @@ int QStatusBar::insertPermanentWidget(int index, QWidget *widget, int stretch)
     QStatusBarPrivate::SBItem* item = new QStatusBarPrivate::SBItem(widget, stretch, true);
 
     int idx = d->indexToLastNonPermanentWidget();
-    if (index < 0 || index > d->items.size() || (idx >= 0 && index <= idx)) {
+    if (Q_UNLIKELY(index < 0 || index > d->items.size() || (idx >= 0 && index <= idx))) {
         qWarning("QStatusBar::insertPermanentWidget: Index out of range (%d), appending widget", index);
         index = d->items.size();
     }
diff --git a/src/widgets/widgets/qtextbrowser.cpp b/src/widgets/widgets/qtextbrowser.cpp
index 2c073342b0..7db9a74afd 100644
--- a/src/widgets/widgets/qtextbrowser.cpp
+++ b/src/widgets/widgets/qtextbrowser.cpp
@@ -292,7 +292,7 @@ void QTextBrowserPrivate::setSource(const QUrl &url)
             txt = data.toString();
 #endif
         }
-        if (txt.isEmpty())
+        if (Q_UNLIKELY(txt.isEmpty()))
             qWarning("QTextBrowser: No document for %s", url.toString().toLatin1().constData());
 
         if (q->isVisible()) {
diff --git a/src/widgets/widgets/qtoolbararealayout.cpp b/src/widgets/widgets/qtoolbararealayout.cpp
index 89e3da1383..dc39221b60 100644
--- a/src/widgets/widgets/qtoolbararealayout.cpp
+++ b/src/widgets/widgets/qtoolbararealayout.cpp
@@ -1128,7 +1128,7 @@ QRect QToolBarAreaLayout::itemRect(const QList<int> &path) const
 QLayoutItem *QToolBarAreaLayout::plug(const QList<int> &path)
 {
     QToolBarAreaLayoutItem *item = this->item(path);
-    if (!item) {
+    if (Q_UNLIKELY(!item)) {
         qWarning() << Q_FUNC_INFO << "No item at" << path;
         return 0;
     }
@@ -1260,7 +1260,7 @@ void QToolBarAreaLayout::saveState(QDataStream &stream) const
                 const QToolBarAreaLayoutItem &item = line.toolBarItems.at(k);
                 QWidget *widget = const_cast<QLayoutItem*>(item.widgetItem)->widget();
                 QString objectName = widget->objectName();
-                if (objectName.isEmpty()) {
+                if (Q_UNLIKELY(objectName.isEmpty())) {
                     qWarning("QMainWindow::saveState(): 'objectName' not set for QToolBar %p '%s'",
                                 widget, widget->windowTitle().toLocal8Bit().constData());
                 }
diff --git a/src/widgets/widgets/qtoolbox.cpp b/src/widgets/widgets/qtoolbox.cpp
index beb70f1283..a37747e138 100644
--- a/src/widgets/widgets/qtoolbox.cpp
+++ b/src/widgets/widgets/qtoolbox.cpp
@@ -521,10 +521,10 @@ QWidget * QToolBox::currentWidget() const
 void QToolBox::setCurrentWidget(QWidget *widget)
 {
     int i = indexOf(widget);
-    if (i >= 0)
-        setCurrentIndex(i);
-    else
+    if (Q_UNLIKELY(i < 0))
         qWarning("QToolBox::setCurrentWidget: widget not contained in tool box");
+    else
+        setCurrentIndex(i);
 }
 
 /*!
diff --git a/src/widgets/widgets/qwidgetlinecontrol.cpp b/src/widgets/widgets/qwidgetlinecontrol.cpp
index 436937be72..6fbe0f9da4 100644
--- a/src/widgets/widgets/qwidgetlinecontrol.cpp
+++ b/src/widgets/widgets/qwidgetlinecontrol.cpp
@@ -309,7 +309,7 @@ void QWidgetLineControl::setSelection(int start, int length)
 {
     commitPreedit();
 
-    if(start < 0 || start > (int)m_text.length()){
+    if (Q_UNLIKELY(start < 0 || start > m_text.size())) {
         qWarning("QWidgetLineControl::setSelection: Invalid start position");
         return;
     }