[Interest] qSwap or std::swap?

[Philippe]

In the Qt doc, it is said that qSwap is obsolete and should never be used
in new code:
http://doc.qt.io/qt-5/qtalgorithms-obsolete.html

But in this recent video from the Qt World Summit 2015, Marc Mutz says the
exact opposite (around time 20:30)
https://www.youtube.com/watch?v=Y3YMA1Ip3ek

A quick test with Qt 5.5.1 on qSwap with QString tends to show Marc is
right (much less assembly code for this call).

So, is it a mistake from the Qt documentation or?...

Philippe