QImageReader fails to load large (over 4GB) tiff file

TIFF* tif = TIFFOpen(fn, "r");
if (tif) {
        uint32 w, h;
        TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &w);
        TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &h);
        m_fullImage = QImage(w, h, QImage::Format_RGBA8888);
        TIFFReadRGBAImage(tif, w, h, (uint32 *)m_fullImage.bits(), 0);
        TIFFClose(tif);
}