[Bug 664431] Re: QT on armel is built with NEON by default

[Thiago Macieira]

My recommendation (as upstream) is that you compile Qt with run-time-
detected Neon support. That is, do not enable -mfpu=neon everywhere, but
let Qt detect that the compiler supports this option and enable only for
the *_neon.cpp files.

I knew that Qt had this supported at UDS, but what I didn't know was
that it was broken. It wasn't runtime detection, it simply turned the
option on for everything. Hence the SIGILL.

I opened a bug report and it was fixed:
http://bugreports.qt.nokia.com/browse/QTBUG-15163

There's still something wrong in the detection machinery (task
QTBUG-15150) which AFAIK doesn't affect the Ubuntu builds. The issue I
know of is a false negative of Neon: it disables Neon even when the
compiler supports. That's the MeeGo bug linked from QTBUG-15150.

-- 
QT on armel is built with NEON by default
https://bugs.launchpad.net/bugs/664431
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