#include <QRegion>
#include <QPolygon>

int main(int argc, char **argv)
{
    QPolygon polygon;

    polygon << QPoint(100, 0);
    polygon << QPoint(-10000000, 2);
    polygon << QPoint(100, 0);

    QRegion region(polygon);

    return 0;
}

==19930== Invalid read of size 4
==19930==    at 0x527E707: InsertionSort(_EdgeTableEntry*) (qregion.cpp:3406)
==19930==    by 0x527F73F: PolygonRegion(QPoint const*, int, int) (qregion.cpp:3676)
==19930==    by 0x52804F9: QRegion::QRegion(QPolygon const&, Qt::FillRule) (qregion.cpp:3871)
==19930==    by 0x400E44: main (main.cpp:12)
==19930==  Address 0x4 is not stack'd, malloc'd or (recently) free'd