diff --git a/src/declarativeimports/core/datamodel.cpp b/src/declarativeimports/core/datamodel.cpp
index cbbe3d5e1..8be4abe95 100644
--- a/src/declarativeimports/core/datamodel.cpp
+++ b/src/declarativeimports/core/datamodel.cpp
@@ -53,6 +53,7 @@ void SortFilterModel::syncRoleNames()
 
     m_roleIds.clear();
     const QHash<int, QByteArray> rNames = roleNames();
+    m_roleIds.reserve(rNames.count());
     for (auto i = rNames.constBegin(); i != rNames.constEnd(); ++i) {
         m_roleIds[i.value()] = i.key();
     }
@@ -62,12 +63,9 @@ void SortFilterModel::syncRoleNames()
     setSortRole(m_sortRole);
 }
 
-int SortFilterModel::roleNameToId(const QString &name)
+int SortFilterModel::roleNameToId(const QString &name) const
 {
-    if (!m_roleIds.contains(name)) {
-        return Qt::DisplayRole;
-    }
-    return m_roleIds.value(name);
+    return m_roleIds.value(name, Qt::DisplayRole);
 }
 
 void SortFilterModel::setModel(QAbstractItemModel *model)
diff --git a/src/declarativeimports/core/datamodel.h b/src/declarativeimports/core/datamodel.h
index f06a51e18..18886193f 100644
--- a/src/declarativeimports/core/datamodel.h
+++ b/src/declarativeimports/core/datamodel.h
@@ -138,7 +138,7 @@ Q_SIGNALS:
     Q_REVISION(1) void filterCallbackChanged(const QJSValue &);
 
 protected:
-    int roleNameToId(const QString &name);  //FIXME TODO KF6: This should have been const.
+    int roleNameToId(const QString &name) const;
     bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const Q_DECL_OVERRIDE;
 
 protected Q_SLOTS: