Use Q_UNLIKELY for every qFatal()/qCritical()

If, after checking a condition, we issue a qFatal()
or a qCritical(), 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.

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 some cases, simplified the expressions newly wrapped
in Q_UNLIKELY as a drive-by.

Change-Id: I67537d62b04bc6977d69254690c5ebbdf98bfd6d
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

41 files changed, 134 insertions, 139 deletions

diff --git a/src/plugins/platforms/android/androidjnimain.cpp b/src/plugins/platforms/android/androidjnimain.cpp
index d419e42cd5..9a96534c38 100644
--- a/src/plugins/platforms/android/androidjnimain.cpp
+++ b/src/plugins/platforms/android/androidjnimain.cpp
@@ -487,7 +487,7 @@ static jboolean startQtApplication(JNIEnv *env, jobject /*object*/, jstring para
         // Obtain a handle to the main library (the library that contains the main() function).
         // This library should already be loaded, and calling dlopen() will just return a reference to it.
         m_mainLibraryHnd = dlopen(m_applicationParams.first().data(), 0);
-        if (m_mainLibraryHnd == nullptr) {
+        if (Q_UNLIKELY(!m_mainLibraryHnd)) {
             qCritical() << "dlopen failed:" << dlerror();
             return false;
         }
@@ -497,7 +497,7 @@ static jboolean startQtApplication(JNIEnv *env, jobject /*object*/, jstring para
         m_main = (Main)dlsym(RTLD_DEFAULT, "main");
     }
 
-    if (!m_main) {
+    if (Q_UNLIKELY(!m_main)) {
         qCritical() << "dlsym failed:" << dlerror();
         qCritical() << "Could not find main method";
         return false;
diff --git a/src/plugins/platforms/android/qandroidinputcontext.cpp b/src/plugins/platforms/android/qandroidinputcontext.cpp
index e3ea048e84..92c0c2cf0f 100644
--- a/src/plugins/platforms/android/qandroidinputcontext.cpp
+++ b/src/plugins/platforms/android/qandroidinputcontext.cpp
@@ -339,7 +339,7 @@ QAndroidInputContext::QAndroidInputContext()
     : QPlatformInputContext(), m_composingTextStart(-1), m_blockUpdateSelection(false),  m_batchEditNestingLevel(0), m_focusObject(0)
 {
     jclass clazz = QJNIEnvironmentPrivate::findClass(QtNativeInputConnectionClassName);
-    if (clazz == NULL) {
+    if (Q_UNLIKELY(!clazz)) {
         qCritical() << "Native registration unable to find class '"
                     << QtNativeInputConnectionClassName
                     << '\'';
@@ -347,7 +347,7 @@ QAndroidInputContext::QAndroidInputContext()
     }
 
     QJNIEnvironmentPrivate env;
-    if (env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0])) < 0) {
+    if (Q_UNLIKELY(env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0])) < 0)) {
         qCritical() << "RegisterNatives failed for '"
                     << QtNativeInputConnectionClassName
                     << '\'';
@@ -355,7 +355,7 @@ QAndroidInputContext::QAndroidInputContext()
     }
 
     clazz = QJNIEnvironmentPrivate::findClass(QtExtractedTextClassName);
-    if (clazz == NULL) {
+    if (Q_UNLIKELY(!clazz)) {
         qCritical() << "Native registration unable to find class '"
                     << QtExtractedTextClassName
                     << '\'';
@@ -364,43 +364,43 @@ QAndroidInputContext::QAndroidInputContext()
 
     m_extractedTextClass = static_cast<jclass>(env->NewGlobalRef(clazz));
     m_classConstructorMethodID = env->GetMethodID(m_extractedTextClass, "<init>", "()V");
-    if (m_classConstructorMethodID == NULL) {
+    if (Q_UNLIKELY(!m_classConstructorMethodID)) {
         qCritical() << "GetMethodID failed";
         return;
     }
 
     m_partialEndOffsetFieldID = env->GetFieldID(m_extractedTextClass, "partialEndOffset", "I");
-    if (m_partialEndOffsetFieldID == NULL) {
+    if (Q_UNLIKELY(!m_partialEndOffsetFieldID)) {
         qCritical() << "Can't find field partialEndOffset";
         return;
     }
 
     m_partialStartOffsetFieldID = env->GetFieldID(m_extractedTextClass, "partialStartOffset", "I");
-    if (m_partialStartOffsetFieldID == NULL) {
+    if (Q_UNLIKELY(!m_partialStartOffsetFieldID)) {
         qCritical() << "Can't find field partialStartOffset";
         return;
     }
 
     m_selectionEndFieldID = env->GetFieldID(m_extractedTextClass, "selectionEnd", "I");
-    if (m_selectionEndFieldID == NULL) {
+    if (Q_UNLIKELY(!m_selectionEndFieldID)) {
         qCritical() << "Can't find field selectionEnd";
         return;
     }
 
     m_selectionStartFieldID = env->GetFieldID(m_extractedTextClass, "selectionStart", "I");
-    if (m_selectionStartFieldID == NULL) {
+    if (Q_UNLIKELY(!m_selectionStartFieldID)) {
         qCritical() << "Can't find field selectionStart";
         return;
     }
 
     m_startOffsetFieldID = env->GetFieldID(m_extractedTextClass, "startOffset", "I");
-    if (m_startOffsetFieldID == NULL) {
+    if (Q_UNLIKELY(!m_startOffsetFieldID)) {
         qCritical() << "Can't find field startOffset";
         return;
     }
 
     m_textFieldID = env->GetFieldID(m_extractedTextClass, "text", "Ljava/lang/String;");
-    if (m_textFieldID == NULL) {
+    if (Q_UNLIKELY(!m_textFieldID)) {
         qCritical() << "Can't find field text";
         return;
     }
diff --git a/src/plugins/platforms/android/qandroidplatformfontdatabase.cpp b/src/plugins/platforms/android/qandroidplatformfontdatabase.cpp
index a8bbec9400..835ca8a10a 100644
--- a/src/plugins/platforms/android/qandroidplatformfontdatabase.cpp
+++ b/src/plugins/platforms/android/qandroidplatformfontdatabase.cpp
@@ -47,7 +47,7 @@ void QAndroidPlatformFontDatabase::populateFontDatabase()
     QString fontpath = fontDir();
     QDir dir(fontpath);
 
-    if (!dir.exists()) {
+    if (Q_UNLIKELY(!dir.exists())) {
         qFatal("QFontDatabase: Cannot find font directory %s - is Qt installed correctly?",
                qPrintable(fontpath));
     }
diff --git a/src/plugins/platforms/android/qandroidplatformintegration.cpp b/src/plugins/platforms/android/qandroidplatformintegration.cpp
index 2a127f5c3c..23d242a95f 100644
--- a/src/plugins/platforms/android/qandroidplatformintegration.cpp
+++ b/src/plugins/platforms/android/qandroidplatformintegration.cpp
@@ -120,14 +120,14 @@ QAndroidPlatformIntegration::QAndroidPlatformIntegration(const QStringList &para
     m_androidPlatformNativeInterface = new QAndroidPlatformNativeInterface();
 
     m_eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
-    if (m_eglDisplay == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(m_eglDisplay == EGL_NO_DISPLAY))
         qFatal("Could not open egl display");
 
     EGLint major, minor;
-    if (!eglInitialize(m_eglDisplay, &major, &minor))
+    if (Q_UNLIKELY(!eglInitialize(m_eglDisplay, &major, &minor)))
         qFatal("Could not initialize egl display");
 
-    if (!eglBindAPI(EGL_OPENGL_ES_API))
+    if (Q_UNLIKELY(!eglBindAPI(EGL_OPENGL_ES_API)))
         qFatal("Could not bind GL_ES API");
 
     m_primaryScreen = new QAndroidPlatformScreen();
diff --git a/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp b/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
index 57d3bfaf22..85f51d7d29 100644
--- a/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
+++ b/src/plugins/platforms/android/qandroidplatformopenglwindow.cpp
@@ -175,7 +175,7 @@ void QAndroidPlatformOpenGLWindow::createEgl(EGLConfig config)
     m_androidSurfaceObject = QJNIObjectPrivate();
     m_eglSurface = eglCreateWindowSurface(m_eglDisplay, config, m_nativeWindow, NULL);
     m_format = q_glFormatFromConfig(m_eglDisplay, config, window()->requestedFormat());
-    if (m_eglSurface == EGL_NO_SURFACE) {
+    if (Q_UNLIKELY(m_eglSurface == EGL_NO_SURFACE)) {
         EGLint error = eglGetError();
         eglTerminate(m_eglDisplay);
         qFatal("EGL Error : Could not create the egl surface: error = 0x%x\n", error);
diff --git a/src/plugins/platforms/android/qandroidplatformtheme.cpp b/src/plugins/platforms/android/qandroidplatformtheme.cpp
index 55bef1a1e8..949d31740a 100644
--- a/src/plugins/platforms/android/qandroidplatformtheme.cpp
+++ b/src/plugins/platforms/android/qandroidplatformtheme.cpp
@@ -203,12 +203,12 @@ QJsonObject AndroidStyle::loadStyleData()
 
     QJsonParseError error;
     QJsonDocument document = QJsonDocument::fromJson(f.readAll(), &error);
-    if (document.isNull()) {
+    if (Q_UNLIKELY(document.isNull())) {
         qCritical() << error.errorString();
         return QJsonObject();
     }
 
-    if (!document.isObject()) {
+    if (Q_UNLIKELY(!document.isObject())) {
         qCritical() << "Style.json does not contain a valid style.";
         return QJsonObject();
     }
diff --git a/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.cpp b/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.cpp
index 154023fb11..418c2e3745 100644
--- a/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.cpp
+++ b/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.cpp
@@ -51,7 +51,7 @@ public:
             HRESULT hr = QWindowsDirect2DContext::instance()->d2dDevice()->CreateDeviceContext(
                         D2D1_DEVICE_CONTEXT_OPTIONS_NONE,
                         &deviceContext);
-            if (FAILED(hr))
+            if (Q_UNLIKELY(FAILED(hr)))
                 qFatal("%s: Couldn't create Direct2D Device Context: %#x", __FUNCTION__, hr);
         }
 
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
index d1814fb85d..789f2fa86f 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
@@ -77,7 +77,7 @@ void QEglFSKmsIntegration::platformInit()
         qCDebug(qLcEglfsKmsDebug) << "Found the following video devices:" << devices;
         d->deleteLater();
 
-        if (devices.isEmpty())
+        if (Q_UNLIKELY(devices.isEmpty()))
             qFatal("Could not find DRM device!");
 
         m_devicePath = devices.first();
@@ -85,7 +85,7 @@ void QEglFSKmsIntegration::platformInit()
     }
 
     m_device = new QEglFSKmsDevice(this, m_devicePath);
-    if (!m_device->open())
+    if (Q_UNLIKELY(!m_device->open()))
         qFatal("Could not open device %s - aborting!", qPrintable(m_devicePath));
 }
 
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
index 1ddcb3b862..b364056b91 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
@@ -52,20 +52,20 @@ QEglFSKmsEglDeviceIntegration::QEglFSKmsEglDeviceIntegration()
 
 void QEglFSKmsEglDeviceIntegration::platformInit()
 {
-    if (!query_egl_device())
+    if (Q_UNLIKELY(!query_egl_device()))
         qFatal("Could not set up EGL device!");
 
     const char *deviceName = m_funcs->query_device_string(m_egl_device, EGL_DRM_DEVICE_FILE_EXT);
-    if (!deviceName)
+    if (Q_UNLIKELY(!deviceName))
         qFatal("Failed to query device name from EGLDevice");
 
     qCDebug(qLcEglfsKmsDebug, "Opening %s", deviceName);
 
     m_dri_fd = drmOpen(deviceName, Q_NULLPTR);
-    if (m_dri_fd < 0)
+    if (Q_UNLIKELY(m_dri_fd < 0))
         qFatal("Could not open DRM device");
 
-    if (!setup_kms())
+    if (Q_UNLIKELY(!setup_kms()))
         qFatal("Could not set up KMS on device %s!", m_device.constData());
 
     qCDebug(qLcEglfsKmsDebug, "DRM/KMS initialized");
@@ -100,14 +100,14 @@ EGLDisplay QEglFSKmsEglDeviceIntegration::createDisplay(EGLNativeDisplayType nat
         display = eglGetDisplay(nativeDisplay);
     }
 
-    if (display == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(display == EGL_NO_DISPLAY))
         qFatal("Could not get EGL display");
 
     EGLint major, minor;
-    if (!eglInitialize(display, &major, &minor))
+    if (Q_UNLIKELY(!eglInitialize(display, &major, &minor)))
         qFatal("Could not initialize egl display");
 
-    if (!eglBindAPI(EGL_OPENGL_ES_API))
+    if (Q_UNLIKELY(!eglBindAPI(EGL_OPENGL_ES_API)))
         qFatal("Failed to bind EGL_OPENGL_ES_API\n");
 
     return display;
@@ -255,8 +255,8 @@ QEglFSWindow *QEglFSKmsEglDeviceIntegration::createWindow(QWindow *window) const
     QEglJetsonTK1Window *eglWindow = new QEglJetsonTK1Window(window, this);
 
     m_funcs->initialize(eglWindow->screen()->display());
-    if (!(m_funcs->has_egl_output_base && m_funcs->has_egl_output_drm && m_funcs->has_egl_stream
-          && m_funcs->has_egl_stream_producer_eglsurface && m_funcs->has_egl_stream_consumer_egloutput))
+    if (Q_UNLIKELY(!(m_funcs->has_egl_output_base && m_funcs->has_egl_output_drm && m_funcs->has_egl_stream &&
+                     m_funcs->has_egl_stream_producer_eglsurface && m_funcs->has_egl_stream_consumer_egloutput)))
         qFatal("Required extensions missing!");
 
     return eglWindow;
@@ -298,7 +298,7 @@ void QEglFSKmsEglDeviceIntegration::waitForVSync(QPlatformSurface *) const
                                  -1, 0, 0,
                                  &m_drm_connector->connector_id, 1,
                                  const_cast<const drmModeModeInfoPtr>(&m_drm_mode));
-        if (ret)
+        if (Q_UNLIKELY(ret))
             qFatal("drmModeSetCrtc failed");
     }
 }
@@ -367,7 +367,7 @@ bool QEglFSKmsEglDeviceIntegration::setup_kms()
         }
     }
 
-    if (crtc == 0)
+    if (Q_UNLIKELY(crtc == 0))
         qFatal("No suitable CRTC available");
 
     m_drm_connector = connector;
@@ -387,7 +387,7 @@ bool QEglFSKmsEglDeviceIntegration::setup_kms()
 bool QEglFSKmsEglDeviceIntegration::query_egl_device()
 {
     m_funcs = new QEGLStreamConvenience;
-    if (!m_funcs->has_egl_device_base)
+    if (Q_UNLIKELY(!m_funcs->has_egl_device_base))
         qFatal("EGL_EXT_device_base missing");
 
     EGLint num_devices = 0;
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
index 4d29b96608..ef586622e2 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
@@ -172,7 +172,7 @@ void QEglFSX11Integration::sendConnectionEvent(xcb_atom_t a)
 void QEglFSX11Integration::platformInit()
 {
     m_display = XOpenDisplay(0);
-    if (!m_display)
+    if (Q_UNLIKELY(!m_display))
         qFatal("Could not open display");
 
     XSetEventQueueOwner(DISPLAY, XCBOwnsEventQueue);
diff --git a/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp b/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
index 064b9f6306..e55a17585e 100644
--- a/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
@@ -155,7 +155,7 @@ void QEGLDeviceIntegration::platformInit()
 
     framebuffer = qt_safe_open(fbDev, O_RDONLY);
 
-    if (framebuffer == -1) {
+    if (Q_UNLIKELY(framebuffer == -1)) {
         qWarning("EGLFS: Failed to open %s", fbDev.constData());
         qFatal("EGLFS: Can't continue without a display");
     }
diff --git a/src/plugins/platforms/eglfs/qeglfsintegration.cpp b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
index 2086ce56e2..001dd76803 100644
--- a/src/plugins/platforms/eglfs/qeglfsintegration.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
@@ -118,11 +118,11 @@ void QEglFSIntegration::initialize()
     qt_egl_device_integration()->platformInit();
 
     m_display = qt_egl_device_integration()->createDisplay(nativeDisplay());
-    if (m_display == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(m_display == EGL_NO_DISPLAY))
         qFatal("Could not open egl display");
 
     EGLint major, minor;
-    if (!eglInitialize(m_display, &major, &minor))
+    if (Q_UNLIKELY(!eglInitialize(m_display, &major, &minor)))
         qFatal("Could not initialize egl display");
 
     m_inputContext = QPlatformInputContextFactory::create();
diff --git a/src/plugins/platforms/eglfs/qeglfswindow.cpp b/src/plugins/platforms/eglfs/qeglfswindow.cpp
index 8301be8c17..b29981bc98 100644
--- a/src/plugins/platforms/eglfs/qeglfswindow.cpp
+++ b/src/plugins/platforms/eglfs/qeglfswindow.cpp
@@ -102,17 +102,15 @@ void QEglFSWindow::create()
     QEglFSScreen *screen = this->screen();
     QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
     if (screen->primarySurface() != EGL_NO_SURFACE) {
-        if (isRaster() && compositor->targetWindow()) {
-            m_format = compositor->targetWindow()->format();
-            return;
-        }
-
+        if (Q_UNLIKELY(!isRaster() || !compositor->targetWindow())) {
 #if !defined(Q_OS_ANDROID) || defined(Q_OS_ANDROID_NO_SDK)
-        // We can have either a single OpenGL window or multiple raster windows.
-        // Other combinations cannot work.
-        qFatal("EGLFS: OpenGL windows cannot be mixed with others.");
+            // We can have either a single OpenGL window or multiple raster windows.
+            // Other combinations cannot work.
+            qFatal("EGLFS: OpenGL windows cannot be mixed with others.");
 #endif
-
+            return;
+        }
+        m_format = compositor->targetWindow()->format();
         return;
     }
 
@@ -122,7 +120,7 @@ void QEglFSWindow::create()
 
     resetSurface();
 
-    if (m_surface == EGL_NO_SURFACE) {
+    if (Q_UNLIKELY(m_surface == EGL_NO_SURFACE)) {
         EGLint error = eglGetError();
         eglTerminate(screen->display());
         qFatal("EGL Error : Could not create the egl surface: error = 0x%x\n", error);
@@ -135,7 +133,7 @@ void QEglFSWindow::create()
         context->setShareContext(qt_gl_global_share_context());
         context->setFormat(m_format);
         context->setScreen(window()->screen());
-        if (!context->create())
+        if (Q_UNLIKELY(!context->create()))
             qFatal("EGLFS: Failed to create compositing context");
         compositor->setTarget(context, window());
     }
diff --git a/src/plugins/platforms/haiku/qhaikuwindow.cpp b/src/plugins/platforms/haiku/qhaikuwindow.cpp
index 9622d12111..1576e7c04e 100644
--- a/src/plugins/platforms/haiku/qhaikuwindow.cpp
+++ b/src/plugins/platforms/haiku/qhaikuwindow.cpp
@@ -127,7 +127,7 @@ QHaikuWindow::QHaikuWindow(QWindow *window)
 
     m_window = haikuWindow;
 
-    if (!m_window)
+    if (Q_UNLIKELY(!m_window))
         qFatal("QHaikuWindow: failed to create window");
 
     setGeometry(rect);
diff --git a/src/plugins/platforms/ios/qioseventdispatcher.mm b/src/plugins/platforms/ios/qioseventdispatcher.mm
index 0e9f176487..e1c6071c38 100644
--- a/src/plugins/platforms/ios/qioseventdispatcher.mm
+++ b/src/plugins/platforms/ios/qioseventdispatcher.mm
@@ -129,7 +129,7 @@ namespace
 
             // Which we verify, just in case
             struct rlimit stackLimit = {0, 0};
-            if (getrlimit(RLIMIT_STACK, &stackLimit) == 0 && stackSize > stackLimit.rlim_cur)
+            if (Q_UNLIKELY(getrlimit(RLIMIT_STACK, &stackLimit) == 0 && stackSize > stackLimit.rlim_cur))
                 qFatal("Unexpectedly exceeded stack limit");
 
             return stackSize;
@@ -250,7 +250,7 @@ static void __attribute__((noinline, noreturn)) user_main_trampoline()
         unsigned int bufferSize = [arg lengthOfBytesUsingEncoding:cStringEncoding] + 1;
         argv[i] = reinterpret_cast<char *>(malloc(bufferSize));
 
-        if (![arg getCString:argv[i] maxLength:bufferSize encoding:cStringEncoding])
+        if (Q_UNLIKELY(![arg getCString:argv[i] maxLength:bufferSize encoding:cStringEncoding]))
             qFatal("Could not convert argv[%d] to C string", i);
     }
 
diff --git a/src/plugins/platforms/ios/qiosintegration.mm b/src/plugins/platforms/ios/qiosintegration.mm
index 0e3da8dce8..72c9286f86 100644
--- a/src/plugins/platforms/ios/qiosintegration.mm
+++ b/src/plugins/platforms/ios/qiosintegration.mm
@@ -70,7 +70,7 @@ QIOSIntegration::QIOSIntegration()
     , m_accessibility(0)
     , m_debugWindowManagement(false)
 {
-    if (![UIApplication sharedApplication]) {
+    if (Q_UNLIKELY(![UIApplication sharedApplication])) {
         qFatal("Error: You are creating QApplication before calling UIApplicationMain.\n" \
                "If you are writing a native iOS application, and only want to use Qt for\n" \
                "parts of the application, a good place to create QApplication is from within\n" \
diff --git a/src/plugins/platforms/minimalegl/qminimaleglscreen.cpp b/src/plugins/platforms/minimalegl/qminimaleglscreen.cpp
index 59062338cb..093a1c689c 100644
--- a/src/plugins/platforms/minimalegl/qminimaleglscreen.cpp
+++ b/src/plugins/platforms/minimalegl/qminimaleglscreen.cpp
@@ -74,19 +74,19 @@ QMinimalEglScreen::QMinimalEglScreen(EGLNativeDisplayType display)
 
     EGLint major, minor;
 
-    if (!eglBindAPI(EGL_OPENGL_ES_API)) {
+    if (Q_UNLIKELY(!eglBindAPI(EGL_OPENGL_ES_API))) {
         qWarning("Could not bind GL_ES API\n");
         qFatal("EGL error");
     }
 
     m_dpy = eglGetDisplay(display);
-    if (m_dpy == EGL_NO_DISPLAY) {
+    if (Q_UNLIKELY(m_dpy == EGL_NO_DISPLAY)) {
         qWarning("Could not open egl display\n");
         qFatal("EGL error");
     }
     qWarning("Opened display %p\n", m_dpy);
 
-    if (!eglInitialize(m_dpy, &major, &minor)) {
+    if (Q_UNLIKELY(!eglInitialize(m_dpy, &major, &minor))) {
         qWarning("Could not initialize egl display\n");
         qFatal("EGL error");
     }
@@ -135,9 +135,9 @@ void QMinimalEglScreen::createAndSetPlatformContext()
 
     EGLNativeWindowType eglWindow = 0;
 #ifdef Q_OPENKODE
-    if (kdInitializeNV() == KD_ENOTINITIALIZED) {
+    if (Q_UNLIKELY(kdInitializeNV() == KD_ENOTINITIALIZED))
         qFatal("Did not manage to initialize openkode");
-    }
+
     KDWindow *window = kdCreateWindow(m_dpy,config,0);
 
     kdRealizeWindow(window,&eglWindow);
@@ -148,7 +148,7 @@ void QMinimalEglScreen::createAndSetPlatformContext()
 #endif
 
     m_surface = eglCreateWindowSurface(m_dpy, config, eglWindow, NULL);
-    if (m_surface == EGL_NO_SURFACE) {
+    if (Q_UNLIKELY(m_surface == EGL_NO_SURFACE)) {
         qWarning("Could not create the egl surface: error = 0x%x\n", eglGetError());
         eglTerminate(m_dpy);
         qFatal("EGL error");
diff --git a/src/plugins/platforms/mirclient/qmirclientclipboard.cpp b/src/plugins/platforms/mirclient/qmirclientclipboard.cpp
index aa2ddf2103..4494847b54 100644
--- a/src/plugins/platforms/mirclient/qmirclientclipboard.cpp
+++ b/src/plugins/platforms/mirclient/qmirclientclipboard.cpp
@@ -100,7 +100,7 @@ void QMirClientClipboard::onDBusClipboardGetContentsFinished(QDBusPendingCallWat
     Q_ASSERT(call == mPendingGetContentsCall.data());
 
     QDBusPendingReply<QByteArray> reply = *call;
-    if (reply.isError()) {
+    if (Q_UNLIKELY(reply.isError())) {
         qCritical("QMirClientClipboard - Failed to get system clipboard contents via D-Bus. %s, %s",
                 qPrintable(reply.error().name()), qPrintable(reply.error().message()));
         // TODO: Might try again later a number of times...
@@ -114,7 +114,7 @@ void QMirClientClipboard::onDBusClipboardGetContentsFinished(QDBusPendingCallWat
 void QMirClientClipboard::onDBusClipboardSetContentsFinished(QDBusPendingCallWatcher *call)
 {
     QDBusPendingReply<void> reply = *call;
-    if (reply.isError()) {
+    if (Q_UNLIKELY(reply.isError())) {
         qCritical("QMirClientClipboard - Failed to set the system clipboard contents via D-Bus. %s, %s",
                 qPrintable(reply.error().name()), qPrintable(reply.error().message()));
         // TODO: Might try again later a number of times...
@@ -148,9 +148,8 @@ void QMirClientClipboard::setupDBus()
             "com.canonical.QtMir.Clipboard",
             "ContentsChanged",
             this, SLOT(updateMimeData(QByteArray)));
-    if (!ok) {
+    if (Q_UNLIKELY(!ok))
         qCritical("QMirClientClipboard - Failed to connect to ContentsChanged signal form the D-Bus system clipboard.");
-    }
 
     mDBusClipboard = new QDBusInterface("com.canonical.QtMir",
             "/com/canonical/QtMir/Clipboard",
diff --git a/src/plugins/platforms/mirclient/qmirclientintegration.cpp b/src/plugins/platforms/mirclient/qmirclientintegration.cpp
index a234f4eac6..87d2002c56 100644
--- a/src/plugins/platforms/mirclient/qmirclientintegration.cpp
+++ b/src/plugins/platforms/mirclient/qmirclientintegration.cpp
@@ -95,7 +95,7 @@ QMirClientClientIntegration::QMirClientClientIntegration()
     // Create new application instance
     mInstance = u_application_instance_new_from_description_with_options(mDesc, mOptions);
 
-    if (mInstance == nullptr)
+    if (Q_UNLIKELY(!mInstance))
         qFatal("QMirClientClientIntegration: connection to Mir server failed. Check that a Mir server is\n"
                "running, and the correct socket is being used and is accessible. The shell may have\n"
                "rejected the incoming connection, so check its log file");
diff --git a/src/plugins/platforms/offscreen/qoffscreenintegration_x11.cpp b/src/plugins/platforms/offscreen/qoffscreenintegration_x11.cpp
index eb704f2dfa..dfaaa43c1d 100644
--- a/src/plugins/platforms/offscreen/qoffscreenintegration_x11.cpp
+++ b/src/plugins/platforms/offscreen/qoffscreenintegration_x11.cpp
@@ -143,7 +143,7 @@ static Window createDummyWindow(QOffscreenX11Info *x11, XVisualInfo *visualInfo)
 static Window createDummyWindow(QOffscreenX11Info *x11, GLXFBConfig config)
 {
     XVisualInfo *visualInfo = glXGetVisualFromFBConfig(x11->display(), config);
-    if (!visualInfo)
+    if (Q_UNLIKELY(!visualInfo))
         qFatal("Could not initialize GLX");
     Window window = createDummyWindow(x11, visualInfo);
     XFree(visualInfo);
@@ -177,7 +177,7 @@ QOffscreenX11GLXContext::QOffscreenX11GLXContext(QOffscreenX11Info *x11, QOpenGL
         d->window = createDummyWindow(x11, config);
     } else {
         XVisualInfo *visualInfo = qglx_findVisualInfo(x11->display(), 0, &d->format);
-        if (!visualInfo)
+        if (Q_UNLIKELY(!visualInfo))
             qFatal("Could not initialize GLX");
         d->context = glXCreateContext(x11->display(), visualInfo, d->shareContext, true);
         if (!d->context && d->shareContext) {
diff --git a/src/plugins/platforms/openwfd/qopenwfdport.cpp b/src/plugins/platforms/openwfd/qopenwfdport.cpp
index 8da1e9bd34..c1646fbdf9 100644
--- a/src/plugins/platforms/openwfd/qopenwfdport.cpp
+++ b/src/plugins/platforms/openwfd/qopenwfdport.cpp
@@ -96,9 +96,8 @@ void QOpenWFDPort::attach()
     mPhysicalSize = QSizeF(physicalWFDSize[0],physicalWFDSize[1]);
 
     WFDint numAvailablePipelines = wfdGetPortAttribi(mDevice->handle(),mPort,WFD_PORT_PIPELINE_ID_COUNT);
-    if (!numAvailablePipelines) {
+    if (Q_UNLIKELY(!numAvailablePipelines))
         qFatal("Not possible to make screen that is not possible to create WFPort with no pipline");
-    }
 
     WFDint pipeIds[numAvailablePipelines];
     wfdGetPortAttribiv(mDevice->handle(),mPort,WFD_PORT_BINDABLE_PIPELINE_IDS,numAvailablePipelines,pipeIds);
@@ -109,9 +108,9 @@ void QOpenWFDPort::attach()
             mDevice-> addToUsedPipelineSet(mPipelineId,this);
 
             mPipeline = wfdCreatePipeline(mDevice->handle(),mPipelineId,WFD_NONE);
-            if (mPipeline == WFD_INVALID_HANDLE) {
+            if (Q_UNLIKELY(mPipeline == WFD_INVALID_HANDLE))
                 qFatal("Failed to create pipeline for port %p", this);
-            }
+
             break;
         }
     }
diff --git a/src/plugins/platforms/qnx/qqnxbuffer.cpp b/src/plugins/platforms/qnx/qqnxbuffer.cpp
index 2c3a42ac7c..8589775fdf 100644
--- a/src/plugins/platforms/qnx/qqnxbuffer.cpp
+++ b/src/plugins/platforms/qnx/qqnxbuffer.cpp
@@ -76,7 +76,7 @@ QQnxBuffer::QQnxBuffer(screen_buffer_t buffer)
             screen_get_buffer_property_pv(buffer, SCREEN_PROPERTY_POINTER, (void **)&dataPtr),
             "Failed to query buffer pointer");
 
-    if (dataPtr == 0)
+    if (Q_UNLIKELY(!dataPtr))
         qFatal("QQNX: buffer pointer is NULL, errno=%d", errno);
 
     // Get format of buffer
@@ -131,13 +131,13 @@ void QQnxBuffer::invalidateInCache()
     qBufferDebug() << Q_FUNC_INFO;
 
     // Verify native buffer exists
-    if (m_buffer == 0)
+    if (Q_UNLIKELY(!m_buffer))
         qFatal("QQNX: can't invalidate cache for null buffer");
 
     // Evict buffer's data from cache
     errno = 0;
     int result = msync(m_image.bits(), m_image.height() * m_image.bytesPerLine(), MS_INVALIDATE | MS_CACHE_ONLY);
-    if (result != 0)
+    if (Q_UNLIKELY(result != 0))
         qFatal("QQNX: failed to invalidate cache, errno=%d", errno);
 }
 
diff --git a/src/plugins/platforms/qnx/qqnxeglwindow.cpp b/src/plugins/platforms/qnx/qqnxeglwindow.cpp
index 77630018e9..8faa474718 100644
--- a/src/plugins/platforms/qnx/qqnxeglwindow.cpp
+++ b/src/plugins/platforms/qnx/qqnxeglwindow.cpp
@@ -59,7 +59,7 @@ QQnxEglWindow::QQnxEglWindow(QWindow *window, screen_context_t context, bool nee
     // Set window usage
     const int val = SCREEN_USAGE_OPENGL_ES2;
     const int result = screen_set_window_property_iv(nativeHandle(), SCREEN_PROPERTY_USAGE, &val);
-    if (result != 0)
+    if (Q_UNLIKELY(result != 0))
         qFatal("QQnxEglWindow: failed to set window alpha usage, errno=%d", errno);
 
     m_requestedBufferSize = shouldMakeFullScreen() ? screen()->geometry().size() : window->geometry().size();
@@ -106,7 +106,7 @@ void QQnxEglWindow::destroyEGLSurface()
     // Destroy EGL surface if it exists
     if (m_eglSurface != EGL_NO_SURFACE) {
         EGLBoolean eglResult = eglDestroySurface(platformOpenGLContext()->getEglDisplay(), m_eglSurface);
-        if (eglResult != EGL_TRUE)
+        if (Q_UNLIKELY(eglResult != EGL_TRUE))
             qFatal("QQNX: failed to destroy EGL surface, err=%d", eglGetError());
     }
 
@@ -118,12 +118,12 @@ void QQnxEglWindow::swapEGLBuffers()
     qEglWindowDebug() << Q_FUNC_INFO;
     // Set current rendering API
     EGLBoolean eglResult = eglBindAPI(EGL_OPENGL_ES_API);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to set EGL API, err=%d", eglGetError());
 
     // Post EGL surface to window
     eglResult = eglSwapBuffers(m_platformOpenGLContext->getEglDisplay(), m_eglSurface);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to swap EGL buffers, err=%d", eglGetError());
 
     windowPosted();
@@ -178,15 +178,15 @@ int QQnxEglWindow::pixelFormat() const
     const QSurfaceFormat format = m_platformOpenGLContext->format();
     // Extract size of color channels from window format
     const int redSize = format.redBufferSize();
-    if (redSize == -1)
+    if (Q_UNLIKELY(redSize == -1))
         qFatal("QQnxWindow: red size not defined");
 
     const int greenSize = format.greenBufferSize();
-    if (greenSize == -1)
+    if (Q_UNLIKELY(greenSize == -1))
         qFatal("QQnxWindow: green size not defined");
 
     const int blueSize = format.blueBufferSize();
-    if (blueSize == -1)
+    if (Q_UNLIKELY(blueSize == -1))
         qFatal("QQnxWindow: blue size not defined");
 
     // select matching native format
diff --git a/src/plugins/platforms/qnx/qqnxglcontext.cpp b/src/plugins/platforms/qnx/qqnxglcontext.cpp
index deac419a36..266de22205 100644
--- a/src/plugins/platforms/qnx/qqnxglcontext.cpp
+++ b/src/plugins/platforms/qnx/qqnxglcontext.cpp
@@ -61,7 +61,7 @@ QQnxGLContext::QQnxGLContext(QOpenGLContext *glContext)
 
     // Set current rendering API
     EGLBoolean eglResult = eglBindAPI(EGL_OPENGL_ES_API);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to set EGL API, err=%d", eglGetError());
 
     // Get colour channel sizes from window format
@@ -113,7 +113,7 @@ QQnxGLContext::QQnxGLContext(QOpenGLContext *glContext)
 
     // Select EGL config based on requested window format
     m_eglConfig = q_configFromGLFormat(ms_eglDisplay, format);
-    if (m_eglConfig == 0)
+    if (Q_UNLIKELY(m_eglConfig == 0))
         qFatal("QQnxGLContext: failed to find EGL config");
 
     QQnxGLContext *glShareContext = static_cast<QQnxGLContext*>(m_glContext->shareHandle());
@@ -121,7 +121,7 @@ QQnxGLContext::QQnxGLContext(QOpenGLContext *glContext)
 
     m_eglContext = eglCreateContext(ms_eglDisplay, m_eglConfig, m_eglShareContext,
                                     contextAttrs(format));
-    if (m_eglContext == EGL_NO_CONTEXT) {
+    if (Q_UNLIKELY(m_eglContext == EGL_NO_CONTEXT)) {
         checkEGLError("eglCreateContext");
         qFatal("QQnxGLContext: failed to create EGL context, err=%d", eglGetError());
     }
@@ -170,13 +170,13 @@ void QQnxGLContext::initializeContext()
 
     // Initialize connection to EGL
     ms_eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
-    if (ms_eglDisplay == EGL_NO_DISPLAY) {
+    if (Q_UNLIKELY(ms_eglDisplay == EGL_NO_DISPLAY)) {
         checkEGLError("eglGetDisplay");
         qFatal("QQnxGLContext: failed to obtain EGL display");
     }
 
     EGLBoolean eglResult = eglInitialize(ms_eglDisplay, 0, 0);
-    if (eglResult != EGL_TRUE) {
+    if (Q_UNLIKELY(eglResult != EGL_TRUE)) {
         checkEGLError("eglInitialize");
         qFatal("QQnxGLContext: failed to initialize EGL display, err=%d", eglGetError());
     }
@@ -198,7 +198,7 @@ bool QQnxGLContext::makeCurrent(QPlatformSurface *surface)
 
     // Set current rendering API
     EGLBoolean eglResult = eglBindAPI(EGL_OPENGL_ES_API);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQnxGLContext: failed to set EGL API, err=%d", eglGetError());
 
     QQnxEglWindow *platformWindow = dynamic_cast<QQnxEglWindow*>(surface);
@@ -227,12 +227,12 @@ void QQnxGLContext::doneCurrent()
 
     // set current rendering API
     EGLBoolean eglResult = eglBindAPI(EGL_OPENGL_ES_API);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to set EGL API, err=%d", eglGetError());
 
     // clear curent EGL context and unbind EGL surface
     eglResult = eglMakeCurrent(ms_eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to clear current EGL context, err=%d", eglGetError());
 }
 
@@ -252,7 +252,7 @@ QFunctionPointer QQnxGLContext::getProcAddress(const QByteArray &procName)
 
     // Set current rendering API
     EGLBoolean eglResult = eglBindAPI(EGL_OPENGL_ES_API);
-    if (eglResult != EGL_TRUE)
+    if (Q_UNLIKELY(eglResult != EGL_TRUE))
         qFatal("QQNX: failed to set EGL API, err=%d", eglGetError());
 
     // Lookup EGL extension function pointer
diff --git a/src/plugins/platforms/qnx/qqnxglobal.cpp b/src/plugins/platforms/qnx/qqnxglobal.cpp
index 01e7675839..4d2599746e 100644
--- a/src/plugins/platforms/qnx/qqnxglobal.cpp
+++ b/src/plugins/platforms/qnx/qqnxglobal.cpp
@@ -44,8 +44,8 @@ void qScreenCheckError(int rc, const char *funcInfo, const char *message, bool c
         rc = screen_flush_context(QQnxIntegration::screenContext(), 0);
     }
 
-    if (rc) {
-        if (critical)
+    if (Q_UNLIKELY(rc)) {
+        if (Q_UNLIKELY(critical))
             qCritical("%s - Screen: %s - Error: %s (%i)", funcInfo, message, strerror(errno), errno);
         else
             qWarning("%s - Screen: %s - Error: %s (%i)", funcInfo, message, strerror(errno), errno);
diff --git a/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp b/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
index ed0db82685..603ddc5c2b 100644
--- a/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
+++ b/src/plugins/platforms/qnx/qqnxinputcontext_imf.cpp
@@ -530,29 +530,28 @@ static bool imfAvailable()
 
     if ( p_imf_client_init == 0 ) {
         void *handle = dlopen("libinput_client.so.1", 0);
-        if ( handle ) {
-            p_imf_client_init = (int32_t (*)()) dlsym(handle, "imf_client_init");
-            p_imf_client_disconnect = (void (*)()) dlsym(handle, "imf_client_disconnect");
-            p_ictrl_open_session = (const input_session_t *(*)(connection_interface_t *))dlsym(handle, "ictrl_open_session");
-            p_ictrl_close_session = (void (*)(input_session_t *))dlsym(handle, "ictrl_close_session");
-            p_ictrl_dispatch_event = (int32_t (*)(event_t *))dlsym(handle, "ictrl_dispatch_event");
-            p_vkb_init_selection_service = (int32_t (*)())dlsym(handle, "vkb_init_selection_service");
-            p_ictrl_get_num_active_sessions = (int32_t (*)())dlsym(handle, "ictrl_get_num_active_sessions");
-        } else {
+        if (Q_UNLIKELY(!handle)) {
             qCritical() << Q_FUNC_INFO << "libinput_client.so.1 is not present - IMF services are disabled.";
             s_imfDisabled = true;
             return false;
         }
-
-        if ( p_imf_client_init && p_ictrl_open_session && p_ictrl_dispatch_event ) {
-            s_imfReady = true;
-        } else {
+        p_imf_client_init = (int32_t (*)()) dlsym(handle, "imf_client_init");
+        p_imf_client_disconnect = (void (*)()) dlsym(handle, "imf_client_disconnect");
+        p_ictrl_open_session = (const input_session_t *(*)(connection_interface_t *))dlsym(handle, "ictrl_open_session");
+        p_ictrl_close_session = (void (*)(input_session_t *))dlsym(handle, "ictrl_close_session");
+        p_ictrl_dispatch_event = (int32_t (*)(event_t *))dlsym(handle, "ictrl_dispatch_event");
+        p_vkb_init_selection_service = (int32_t (*)())dlsym(handle, "vkb_init_selection_service");
+        p_ictrl_get_num_active_sessions = (int32_t (*)())dlsym(handle, "ictrl_get_num_active_sessions");
+
+        if (Q_UNLIKELY(!p_imf_client_init || !p_ictrl_open_session || !p_ictrl_dispatch_event)) {
             p_ictrl_open_session = 0;
             p_ictrl_dispatch_event = 0;
             s_imfDisabled = true;
             qCritical() << Q_FUNC_INFO << "libinput_client.so.1 did not contain the correct symbols, library mismatch? IMF services are disabled.";
             return false;
         }
+
+        s_imfReady = true;
     }
 
     return s_imfReady;
@@ -581,7 +580,7 @@ QQnxInputContext::QQnxInputContext(QQnxIntegration *integration, QQnxAbstractVir
     Q_ASSERT(sInputContextInstance == 0);
     sInputContextInstance = this;
 
-    if (p_imf_client_init() != 0) {
+    if (Q_UNLIKELY(p_imf_client_init() != 0)) {
         s_imfInitFailed = true;
         qCritical("imf_client_init failed - IMF services will be unavailable");
     }
diff --git a/src/plugins/platforms/qnx/qqnxintegration.cpp b/src/plugins/platforms/qnx/qqnxintegration.cpp
index 57f8213a4e..36d59ef134 100644
--- a/src/plugins/platforms/qnx/qqnxintegration.cpp
+++ b/src/plugins/platforms/qnx/qqnxintegration.cpp
@@ -425,7 +425,7 @@ void QQnxIntegration::createDisplays()
                                                 &displayCount);
     Q_SCREEN_CRITICALERROR(result, "Failed to query display count");
 
-    if (displayCount < 1) {
+    if (Q_UNLIKELY(displayCount < 1)) {
         // Never happens, even if there's no display, libscreen returns 1
         qFatal("QQnxIntegration: displayCount=%d", displayCount);
     }
diff --git a/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp b/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
index aa47b5409b..d7221a9185 100644
--- a/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
+++ b/src/plugins/platforms/qnx/qqnxnavigatoreventnotifier.cpp
@@ -102,7 +102,7 @@ void QQnxNavigatorEventNotifier::parsePPS(const QByteArray &ppsData, QByteArray
     QList<QByteArray> lines = ppsData.split('\n');
 
     // validate pps object
-    if (lines.size() == 0 || lines.at(0) != "@control")
+    if (Q_UNLIKELY(lines.empty() || lines.at(0) != "@control"))
         qFatal("QQNX: unrecognized pps object, data=%s", ppsData.constData());
 
     // parse pps object attributes and extract values
@@ -160,7 +160,7 @@ void QQnxNavigatorEventNotifier::replyPPS(const QByteArray &res, const QByteArra
     // send pps message to navigator
     errno = 0;
     int bytes = write(m_fd, ppsData.constData(), ppsData.size());
-    if (bytes == -1)
+    if (Q_UNLIKELY(bytes == -1))
         qFatal("QQNX: failed to write navigator pps, errno=%d", errno);
 }
 
@@ -198,7 +198,7 @@ void QQnxNavigatorEventNotifier::readData()
     // attempt to read pps data
     errno = 0;
     int bytes = qt_safe_read(m_fd, buffer, ppsBufferSize - 1);
-    if (bytes == -1)
+    if (Q_UNLIKELY(bytes == -1))
         qFatal("QQNX: failed to read navigator pps, errno=%d", errno);
 
     // check if pps data was received
diff --git a/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp b/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
index c3b088ae5f..d5bdbb3ec6 100644
--- a/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
+++ b/src/plugins/platforms/qnx/qqnxnavigatorpps.cpp
@@ -100,7 +100,7 @@ bool QQnxNavigatorPps::sendPpsMessage(const QByteArray &message, const QByteArra
     // send pps message to navigator
     errno = 0;
     int bytes = qt_safe_write(m_fd, ppsMessage.constData(), ppsMessage.size());
-    if (bytes == -1)
+    if (Q_UNLIKELY(bytes == -1))
         qFatal("QQNX: failed to write navigator pps, errno=%d", errno);
 
     // allocate buffer for pps data
@@ -110,7 +110,7 @@ bool QQnxNavigatorPps::sendPpsMessage(const QByteArray &message, const QByteArra
     do {
         errno = 0;
         bytes = qt_safe_read(m_fd, buffer, ppsBufferSize - 1);
-        if (bytes == -1)
+        if (Q_UNLIKELY(bytes == -1))
             qFatal("QQNX: failed to read navigator pps, errno=%d", errno);
     } while (bytes == 0);
 
@@ -125,7 +125,7 @@ bool QQnxNavigatorPps::sendPpsMessage(const QByteArray &message, const QByteArra
     parsePPS(ppsData, responseFields);
 
     if (responseFields.contains("res") && responseFields.value("res") == message) {
-        if (responseFields.contains("err")) {
+        if (Q_UNLIKELY(responseFields.contains("err"))) {
             qCritical() << "navigator responded with error: " << responseFields.value("err");
             return false;
         }
@@ -142,7 +142,7 @@ void QQnxNavigatorPps::parsePPS(const QByteArray &ppsData, QHash<QByteArray, QBy
     QList<QByteArray> lines = ppsData.split('\n');
 
     // validate pps object
-    if (lines.size() == 0 || lines.at(0) != "@control")
+    if (Q_UNLIKELY(lines.empty() || lines.at(0) != "@control"))
         qFatal("QQNX: unrecognized pps object, data=%s", ppsData.constData());
 
     // parse pps object attributes and extract values
diff --git a/src/plugins/platforms/qnx/qqnxrasterwindow.cpp b/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
index 6a346e2bb4..30103b4b9a 100644
--- a/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
+++ b/src/plugins/platforms/qnx/qqnxrasterwindow.cpp
@@ -61,7 +61,7 @@ QQnxRasterWindow::QQnxRasterWindow(QWindow *window, screen_context_t context, bo
 
     const int val = SCREEN_USAGE_NATIVE | SCREEN_USAGE_READ | SCREEN_USAGE_WRITE;
     const int result = screen_set_window_property_iv(nativeHandle(), SCREEN_PROPERTY_USAGE, &val);
-    if (result != 0)
+    if (Q_UNLIKELY(result != 0))
         qFatal("QQnxRasterWindow: failed to set window alpha usage, errno=%d", errno);
 }
 
diff --git a/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp b/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
index 4baabbb4fa..01a54a8a5e 100644
--- a/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
+++ b/src/plugins/platforms/qnx/qqnxscreeneventhandler.cpp
@@ -579,12 +579,12 @@ void QQnxScreenEventHandler::handlePropertyEvent(screen_event_t event)
 
     errno = 0;
     screen_window_t window = 0;
-    if (screen_get_event_property_pv(event, SCREEN_PROPERTY_WINDOW, (void**)&window) != 0)
+    if (Q_UNLIKELY(screen_get_event_property_pv(event, SCREEN_PROPERTY_WINDOW, (void**)&window) != 0))
         qFatal("QQnx: failed to query window property, errno=%d", errno);
 
     errno = 0;
     int property;
-    if (screen_get_event_property_iv(event, SCREEN_PROPERTY_NAME, &property) != 0)
+    if (Q_UNLIKELY(screen_get_event_property_iv(event, SCREEN_PROPERTY_NAME, &property) != 0))
         qFatal("QQnx: failed to query window property, errno=%d", errno);
 
     switch (property) {
@@ -601,7 +601,7 @@ void QQnxScreenEventHandler::handleKeyboardFocusPropertyEvent(screen_window_t wi
 {
     errno = 0;
     int focus = 0;
-    if (window && screen_get_window_property_iv(window, SCREEN_PROPERTY_KEYBOARD_FOCUS, &focus) != 0)
+    if (Q_UNLIKELY(window && screen_get_window_property_iv(window, SCREEN_PROPERTY_KEYBOARD_FOCUS, &focus) != 0))
         qFatal("QQnx: failed to query keyboard focus property, errno=%d", errno);
 
     QWindow *focusWindow = QQnxIntegration::window(window);
diff --git a/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp b/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
index 2c7a28e835..33e5cf2947 100644
--- a/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
+++ b/src/plugins/platforms/qnx/qqnxvirtualkeyboardpps.cpp
@@ -127,7 +127,7 @@ bool QQnxVirtualKeyboardPps::connect()
     }
 
     m_buffer = new char[ms_bufferSize];
-    if (!m_buffer) {
+    if (Q_UNLIKELY(!m_buffer)) {
         qCritical("QQnxVirtualKeyboard: Unable to allocate buffer of %d bytes. "
                   "Size is unavailable.",  ms_bufferSize);
         return false;
@@ -170,7 +170,7 @@ void QQnxVirtualKeyboardPps::ppsDataReady()
         return;
 
     // nread is the real space necessary, not the amount read.
-    if (static_cast<size_t>(nread) > ms_bufferSize - 1) {
+    if (Q_UNLIKELY(static_cast<size_t>(nread) > ms_bufferSize - 1)) {
         qCritical("QQnxVirtualKeyboard: Keyboard buffer size too short; need %u.", nread + 1);
         connect(); // reconnect
         return;
@@ -184,7 +184,7 @@ void QQnxVirtualKeyboardPps::ppsDataReady()
 #endif
 
     const char *value;
-    if (pps_decoder_get_string(m_decoder, "error", &value) == PPS_DECODER_OK) {
+    if (Q_UNLIKELY(pps_decoder_get_string(m_decoder, "error", &value) == PPS_DECODER_OK)) {
         qCritical("QQnxVirtualKeyboard: Keyboard PPS decoder error: %s", value ? value : "[null]");
         return;
     }
@@ -214,11 +214,11 @@ void QQnxVirtualKeyboardPps::handleKeyboardInfoMessage()
 {
     int newHeight = 0;
 
-    if (pps_decoder_push(m_decoder, "dat") != PPS_DECODER_OK) {
+    if (Q_UNLIKELY(pps_decoder_push(m_decoder, "dat") != PPS_DECODER_OK)) {
         qCritical("QQnxVirtualKeyboard: Keyboard PPS dat object not found");
         return;
     }
-    if (pps_decoder_get_int(m_decoder, "size", &newHeight) != PPS_DECODER_OK) {
+    if (Q_UNLIKELY(pps_decoder_get_int(m_decoder, "size", &newHeight) != PPS_DECODER_OK)) {
         qCritical("QQnxVirtualKeyboard: Keyboard PPS size field not found");
         return;
     }
diff --git a/src/plugins/platforms/qnx/qqnxwindow.cpp b/src/plugins/platforms/qnx/qqnxwindow.cpp
index c081aa6d28..6adc352e2d 100644
--- a/src/plugins/platforms/qnx/qqnxwindow.cpp
+++ b/src/plugins/platforms/qnx/qqnxwindow.cpp
@@ -372,7 +372,7 @@ void QQnxWindow::setBufferSize(const QSize &size)
         screen_get_window_property_iv(m_window, SCREEN_PROPERTY_RENDER_BUFFER_COUNT, &bufferCount),
         "Failed to query render buffer count");
 
-    if (bufferCount != MAX_BUFFER_COUNT) {
+    if (Q_UNLIKELY(bufferCount != MAX_BUFFER_COUNT)) {
         qFatal("QQnxWindow: invalid buffer count. Expected = %d, got = %d.",
                 MAX_BUFFER_COUNT, bufferCount);
     }
@@ -450,10 +450,10 @@ void QQnxWindow::removeFromParent()
     qWindowDebug() << Q_FUNC_INFO << "window =" << window();
     // Remove from old Hierarchy position
     if (m_parentWindow) {
-        if (m_parentWindow->m_childWindows.removeAll(this))
-            m_parentWindow = 0;
-        else
+        if (Q_UNLIKELY(!m_parentWindow->m_childWindows.removeAll(this)))
             qFatal("QQnxWindow: Window Hierarchy broken; window has parent, but parent hasn't got child.");
+        else
+            m_parentWindow = 0;
     } else if (m_screen) {
         m_screen->removeWindow(this);
     }
diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 5cda6379de..82cc1deb23 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -187,7 +187,7 @@ void QWindowsUser32DLL::init()
     // MinGW (g++ 3.4.5) accepts only C casts.
     setLayeredWindowAttributes = (SetLayeredWindowAttributes)(library.resolve("SetLayeredWindowAttributes"));
     updateLayeredWindow = (UpdateLayeredWindow)(library.resolve("UpdateLayeredWindow"));
-    if (!setLayeredWindowAttributes || !updateLayeredWindow)
+    if (Q_UNLIKELY(!setLayeredWindowAttributes || !updateLayeredWindow))
         qFatal("This version of Windows is not supported (User32.dll is missing the symbols 'SetLayeredWindowAttributes', 'UpdateLayeredWindow').");
 
     updateLayeredWindowIndirect = (UpdateLayeredWindowIndirect)(library.resolve("UpdateLayeredWindowIndirect"));
diff --git a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
index a30e545807..bb7d0fd8d7 100644
--- a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
+++ b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
@@ -1582,7 +1582,7 @@ LOGFONT QWindowsFontDatabase::fontDefToLOGFONT(const QFontDef &request)
     lf.lfPitchAndFamily = DEFAULT_PITCH | hint;
 
     QString fam = request.family;
-    if (fam.size() >= LF_FACESIZE) {
+    if (Q_UNLIKELY(fam.size() >= LF_FACESIZE)) {
         qCritical("%s: Family name '%s' is too long.", __FUNCTION__, qPrintable(fam));
         fam.truncate(LF_FACESIZE - 1);
     }
diff --git a/src/plugins/platforms/windows/qwindowsnativeimage.cpp b/src/plugins/platforms/windows/qwindowsnativeimage.cpp
index 66e64e64b4..56e18e20d7 100644
--- a/src/plugins/platforms/windows/qwindowsnativeimage.cpp
+++ b/src/plugins/platforms/windows/qwindowsnativeimage.cpp
@@ -96,7 +96,7 @@ static inline HBITMAP createDIB(HDC hdc, int width, int height,
     void *bits = 0;
     HBITMAP bitmap = CreateDIBSection(hdc, reinterpret_cast<BITMAPINFO *>(&bmi),
                                       DIB_RGB_COLORS, &bits, 0, 0);
-    if (!bitmap || !bits)
+    if (Q_UNLIKELY(!bitmap || !bits))
         qFatal("%s: CreateDIBSection failed.", __FUNCTION__);
 
     *bitsIn = (uchar*)bits;
diff --git a/src/plugins/platforms/winrt/qwinrteglcontext.cpp b/src/plugins/platforms/winrt/qwinrteglcontext.cpp
index 3fd0278360..1008e1c5e8 100644
--- a/src/plugins/platforms/winrt/qwinrteglcontext.cpp
+++ b/src/plugins/platforms/winrt/qwinrteglcontext.cpp
@@ -55,7 +55,7 @@ struct WinRTEGLDisplay
 {
     WinRTEGLDisplay() {
         eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
-        if (eglDisplay == EGL_NO_DISPLAY)
+        if (Q_UNLIKELY(eglDisplay == EGL_NO_DISPLAY))
             qCritical("Failed to initialize EGL display: 0x%x", eglGetError());
     }
     ~WinRTEGLDisplay() {
@@ -114,10 +114,10 @@ void QWinRTEGLContext::initialize()
         EGL_NONE,
     };
     g->eglDisplay = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, displayAttributes);
-    if (g->eglDisplay == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(g->eglDisplay == EGL_NO_DISPLAY))
         qCritical("Failed to initialize EGL display: 0x%x", eglGetError());
 
-    if (!eglInitialize(g->eglDisplay, nullptr, nullptr))
+    if (Q_UNLIKELY(!eglInitialize(g->eglDisplay, nullptr, nullptr)))
         qCritical("Failed to initialize EGL: 0x%x", eglGetError());
 
     d->eglConfig = q_configFromGLFormat(g->eglDisplay, d->format);
diff --git a/src/plugins/platforms/winrt/qwinrtwindow.cpp b/src/plugins/platforms/winrt/qwinrtwindow.cpp
index bec94c1e51..8a53047d1e 100644
--- a/src/plugins/platforms/winrt/qwinrtwindow.cpp
+++ b/src/plugins/platforms/winrt/qwinrtwindow.cpp
@@ -180,7 +180,7 @@ QWinRTWindow::~QWinRTWindow()
 
     EGLBoolean value = eglDestroySurface(d->display, d->surface);
     d->surface = EGL_NO_SURFACE;
-    if (value == EGL_FALSE)
+    if (Q_UNLIKELY(value == EGL_FALSE))
         qCritical("Failed to destroy EGL window surface: 0x%x", eglGetError());
 }
 
@@ -321,7 +321,7 @@ void QWinRTWindow::createEglSurface(EGLDisplay display, EGLConfig config)
             d->surface = eglCreateWindowSurface(display, config,
                                                 reinterpret_cast<EGLNativeWindowType>(winId()),
                                                 nullptr);
-            if (d->surface == EGL_NO_SURFACE)
+            if (Q_UNLIKELY(d->surface == EGL_NO_SURFACE))
                 qCritical("Failed to create EGL window surface: 0x%x", eglGetError());
             return S_OK;
         });
diff --git a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
index 37f01d4eed..e1fb63fbc4 100644
--- a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
+++ b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
@@ -99,7 +99,7 @@ static Window createDummyWindow(Display *dpy, XVisualInfo *visualInfo, int scree
 static Window createDummyWindow(Display *dpy, GLXFBConfig config, int screenNumber, Window rootWin)
 {
     XVisualInfo *visualInfo = glXGetVisualFromFBConfig(dpy, config);
-    if (!visualInfo)
+    if (Q_UNLIKELY(!visualInfo))
         qFatal("Could not initialize GLX");
     Window window = createDummyWindow(dpy, visualInfo, screenNumber, rootWin);
     XFree(visualInfo);
@@ -301,7 +301,7 @@ void QGLXContext::init(QXcbScreen *screen, QPlatformOpenGLContext *share)
 
         // Note that m_format gets updated with the used surface format
         visualInfo = qglx_findVisualInfo(m_display, screen->screenNumber(), &m_format);
-        if (!visualInfo)
+        if (Q_UNLIKELY(!visualInfo))
             qFatal("Could not initialize GLX");
         m_context = glXCreateContext(m_display, visualInfo, m_shareContext, true);
         if (!m_context && m_shareContext) {
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 50d49ca798..ff39b24e93 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -521,7 +521,7 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, bool canGra
     m_connection = xcb_connect(m_displayName.constData(), &m_primaryScreenNumber);
 #endif //XCB_USE_XLIB
 
-    if (!m_connection || xcb_connection_has_error(m_connection))
+    if (Q_UNLIKELY(!m_connection || xcb_connection_has_error(m_connection)))
         qFatal("QXcbConnection: Could not connect to display %s", m_displayName.constData());
 
 
@@ -553,7 +553,7 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, bool canGra
     initializeXFixes();
     initializeScreens();
 
-    if (m_screens.isEmpty())
+    if (Q_UNLIKELY(m_screens.isEmpty()))
         qFatal("QXcbConnection: no screens available");
 
     initializeXRender();
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 4bd4639833..3e01a90402 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -395,7 +395,7 @@ void QXcbWindow::create()
         if (!visualInfo)
             visualInfo = static_cast<XVisualInfo *>(createVisual());
 
-        if (!visualInfo && window()->surfaceType() == QSurface::OpenGLSurface)
+        if (Q_UNLIKELY(!visualInfo && window()->surfaceType() == QSurface::OpenGLSurface))
             qFatal("Could not initialize OpenGL");
 
         if (!visualInfo && window()->surfaceType() == QSurface::RasterGLSurface) {