More startOfDay() fixes, in tst_bench_QDateTime

Update a QDateTime benchmark to use QDate::startOfDay() when setting
up its lists of date-times in helper functions, and to use noon as the
moment in the day in a creation test. Also move creation of a QTime
outside the loop: we're testing speed of creation of QDateTime here,
not QTime (and were already using the most trivial QTime constructor).

Change-Id: I26bf3369aae84a802ab03791f7341e107fede87c
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 5 insertions, 4 deletions

diff --git a/tests/benchmarks/corelib/time/qdatetime/tst_bench_qdatetime.cpp b/tests/benchmarks/corelib/time/qdatetime/tst_bench_qdatetime.cpp
index 302cf80abf..59ef9a1e68 100644
--- a/tests/benchmarks/corelib/time/qdatetime/tst_bench_qdatetime.cpp
+++ b/tests/benchmarks/corelib/time/qdatetime/tst_bench_qdatetime.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -107,7 +107,7 @@ QList<QDateTime> tst_QDateTime::daily(qint64 start, qint64 end)
     QList<QDateTime> list;
     list.reserve(end - start);
     for (int jd = start; jd < end; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+        list.append(QDateTime(QDate::fromJulianDay(jd).startOfDay()));
     return list;
 }
 
@@ -117,15 +117,16 @@ QList<QDateTime> tst_QDateTime::norse(qint64 start, qint64 end)
     QList<QDateTime> list;
     list.reserve(end - start);
     for (int jd = start; jd < end; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+        list.append(QDateTime(QDate::fromJulianDay(jd).startOfDay(cet)));
     return list;
 }
 
 void tst_QDateTime::create()
 {
+    const QTime noon = QTime::fromMSecsSinceStartOfDay(43200);
     QBENCHMARK {
         for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd) {
-            QDateTime test(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0));
+            QDateTime test(QDate::fromJulianDay(jd), noon);
             Q_UNUSED(test);
         }
     }