QMap - improve QMap stl-map ctor

We can insert directly on the most left-most Node.

We always enforce an insert here (unlike the insert call),
but that is not a problem since the keys in a std::map are unique.

Change-Id: Ib409b90ffc57a5a43dab4a4b08d34f6fdabd057f
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/benchmarks/corelib/tools/qmap/main.cpp b/tests/benchmarks/corelib/tools/qmap/main.cpp
index 4d9833b7a1..c11e54ff1d 100644
--- a/tests/benchmarks/corelib/tools/qmap/main.cpp
+++ b/tests/benchmarks/corelib/tools/qmap/main.cpp
@@ -62,6 +62,8 @@ private slots:
     void iteration();
     void toStdMap();
     void iterator_begin();
+
+    void ctorStdMap();
 };
 
 
@@ -189,6 +191,19 @@ void tst_QMap::iterator_begin()
     }
 }
 
+void tst_QMap::ctorStdMap()
+{
+    std::map<int, int> map;
+    for (int i = 0; i < 100000; ++i)
+        map.insert(std::pair<int, int>(i, i));
+
+    QBENCHMARK {
+        QMap<int, int> qmap(map);
+        qmap.constBegin();
+    }
+}
+
+
 QTEST_MAIN(tst_QMap)
 
 #include "main.moc"