QWidget::setParent calls q_evaluateRhiRecursive which is slow

Hello,
I have a case where I create a relatively large amount of widgets (1000-ish). This used to be trivially very fast but since recent Qt I observed some performance degradation, leading to multiple seconds of wait when creating my widget.

When profiling, it seems to call q_evaluateRhiRecursive on every reparenting call, which seems to be a performance bottleneck: here is a trace I recorded with Hotspot ; the huge majority of the time is spent in these calls: