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>

1 files changed, 2 insertions, 2 deletions

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;
     }