MinGW crashes in ucstrncmp (SSE2 path)

Program received signal SIGSEGV, Segmentation fault.
ucstrncmp (a=0x136d7568, b=0x136d72b8, l=3)
    at D:\dev\qt\qt-dev\src\qtbase\src\corelib\tools\qstring.cpp:460
460             m128i a_data = _mm_loadu_si128((m128i*)ptr);
(gdb) bt
#0  ucstrncmp (a=0x136d7568, b=0x136d72b8, l=3)
    at D:\dev\qt\qt-dev\src\qtbase\src\corelib\tools\qstring.cpp:460
#1  0x6b7f842e in qMemEquals (a=0x136d7558, b=0x136d72a8, length=11)
    at D:\dev\qt\qt-dev\src\qtbase\src\corelib\tools\qstring.cpp:621
#2  0x6b7fa819 in operator== (s1=..., s2=...)
    at D:\dev\qt\qt-dev\src\qtbase\src\corelib\tools\qstring.cpp:2504
#3  0x629298af in QHashNode<QString, QHashDummyValue>::same_key (this=0x136d72f0, h0=3111004456,
    key0=...) at ../../../../include/QtCore/../../../../src/qtbase/src/corelib/tools/qhash.h:215
#4  0x629258f0 in QHash<QString, QHashDummyValue>::findNode (this=0x136d5764, akey=...,
    ahp=0x28f14c)
    at ../../../../include/QtCore/../../../../src/qtbase/src/corelib/tools/qhash.h:929
#5  0x629108da in QHash<QString, QHashDummyValue>::insert (this=0x136d5764, akey=..., avalue=...)
    at ../../../../include/QtCore/../../../../src/qtbase/src/corelib/tools/qhash.h:778
#6  0x6290fe2c in QSet<QString>::insert (this=0x136d5764, value=...)
    at ../../../../include/QtCore/../../../../src/qtbase/src/corelib/tools/qset.h:194
#7  0x62857673 in storeFont (f=0x63aaa8, textmetric=0x63ac14, type=2, namesSetIn=325932900)
    at D:\dev\qt\qt-dev\src\qtbase\src\plugins\platforms\windows\qwindowsfontdatabase.cpp:949
#8  0x7678c4af in MaskBlt () from C:\Windows\syswow64\gdi32.dll
#9  0x7678c587 in GDI32!EnumFontFamiliesExW () from C:\Windows\syswow64\gdi32.dll
#10 0x62857929 in QWindowsFontDatabase::populate (this=0x136d5760, family=...)
    at D:\dev\qt\qt-dev\src\qtbase\src\plugins\platforms\windows\qwindowsfontdatabase.cpp:991
#11 0x628576c8 in QWindowsFontDatabase::populateFontDatabase (this=0x136d5760)
    at D:\dev\qt\qt-dev\src\qtbase\src\plugins\platforms\windows\qwindowsfontdatabase.cpp:959
#12 0x01f43cbc in initializeDb ()
    at D:/dev/qt/qt-dev/src/qtbase/src/gui/text/qfontdatabase_qpa.cpp:145
#13 0x01f443b5 in QFontDatabase::findFont (script=2, fp=0x3ff0c8, request=..., multi=true)
    at D:/dev/qt/qt-dev/src/qtbase/src/gui/text/qfontdatabase_qpa.cpp:295
#14 0x01f44e56 in QFontDatabase::load (d=0x3ff0c8, script=2)
    at D:/dev/qt/qt-dev/src/qtbase/src/gui/text/qfontdatabase_qpa.cpp:442
#15 0x01f2dd01 in QFontPrivate::engineForScript (this=0x3ff0c8, script=2)
    at D:\dev\qt\qt-dev\src\qtbase\src\gui\text\qfont.cpp:218
#16 0x01f3e610 in QFontMetrics::height (this=0x28f6f0)
    at D:\dev\qt\qt-dev\src\qtbase\src\gui\text\qfontmetrics.cpp:305
#17 0x09c5b883 in QTabBar::tabSizeHint (this=0x136d3fb0, index=0)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabbar.cpp:1376
#18 0x09c58153 in QTabBarPrivate::layoutTabs (this=0x136d42d0)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabbar.cpp:445
#19 0x09c5aef2 in QTabBar::sizeHint (this=0x136d3fb0)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabbar.cpp:1266
#20 0x09c5fd85 in QTabWidget::initStyleOption (this=0x136d3a10, option=0x28f9e8)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabwidget.cpp:295
#21 0x09c60c7c in QTabWidget::setUpLayout (this=0x136d3a10, onlyCheck=false)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabwidget.cpp:780
#22 0x09c6034b in QTabWidget::insertTab (this=0x136d3a10, index=0, w=0x136d4ce0, icon=...,
    label=...) at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabwidget.cpp:467
#23 0x09c602b1 in QTabWidget::insertTab (this=0x136d3a10, index=-1, w=0x136d4ce0, label=...)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabwidget.cpp:445
#24 0x09c60238 in QTabWidget::addTab (this=0x136d3a10, child=0x136d4ce0, label=...)
    at D:\dev\qt\qt-dev\src\qtbase\src\widgets\widgets\qtabwidget.cpp:391
#25 0x00409c6b in Ui_BearerMonitor::setupUi (this=0x28fdd0, BearerMonitor=0x28fdb8)
    at .uic/ui_bearermonitor_640_480.h:314
#26 0x0040177c in BearerMonitor::BearerMonitor (this=0x28fdb8, parent=0x0)
    at D:\dev\qt\qt-dev\src\qtbase\examples\network\bearermonitor\bearermonitor.cpp:58
#27 0x00401682 in main (argc=1, argv=0x3f3508)
    at D:\dev\qt\qt-dev\src\qtbase\examples\network\bearermonitor\main.cpp:52