http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58678
--- Comment #49 from David Kredba <nheghathivhistha at gmail dot com> --- I am still getting this with revision 208612 without -flto: CMakeFiles/kritametadataeditor.dir/kis_meta_data_editor.cc.o: In function `KisMetaDataEditor::KisMetaDataEditor(QWidget*, KisMetaData::Store*)': /var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:79: undefined reference to `QUiLoader::QUiLoader(QObject*)' /var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:82: undefined reference to `QUiLoader::load(QIODevice*, QWidget*)' /var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:85: undefined reference to `QUiLoader::~QUiLoader()' /var/tmp/portage/app-office/calligra-2.8.0/work/calligra-2.8.0/krita/plugins/extensions/metadataeditor/kis_meta_data_editor.cc:79: undefined reference to `QUiLoader::~QUiLoader()' collect2: error: ld returned 1 exit status And I was not able to follow Markus's instructions about how to get it working with -flto by copying that "qHash 3 row" from .h to .cpp. Thank you.