QVector: Save one copy-CTOR call if we don't realloc

Change-Id: Ie0f2eb922500bc3d76852939cf2c5d28d65a43ae
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/src/corelib/tools/qvector.h b/src/corelib/tools/qvector.h
index 9d5b749e79..eed5d17cad 100644
--- a/src/corelib/tools/qvector.h
+++ b/src/corelib/tools/qvector.h
@@ -600,16 +600,23 @@ Q_OUTOFLINE_TEMPLATE T QVector<T>::value(int i, const T &defaultValue) const
 template <typename T>
 void QVector<T>::append(const T &t)
 {
-    const T copy(t);
     const bool isTooSmall = uint(d->size + 1) > d->alloc;
     if (!isDetached() || isTooSmall) {
+        const T copy(t);
         QArrayData::AllocationOptions opt(isTooSmall ? QArrayData::Grow : QArrayData::Default);
         reallocData(d->size, isTooSmall ? d->size + 1 : d->alloc, opt);
+
+        if (QTypeInfo<T>::isComplex)
+            new (d->end()) T(copy);
+        else
+            *d->end() = copy;
+
+    } else {
+        if (QTypeInfo<T>::isComplex)
+            new (d->end()) T(t);
+        else
+            *d->end() = t;
     }
-    if (QTypeInfo<T>::isComplex)
-        new (d->end()) T(copy);
-    else
-        *d->end() = copy;
     ++d->size;
 }