Bug#431608: g++-4.2: Abysmal performance compiling python-qt3
On Wednesday 25 July 2007 11:22:13 am Matthias Klose wrote:
> Daniel Schepler writes:
> > It looks like the original bug message didn't get forwarded to
> > debian-gcc, possibly because it included a large preprocessed source
> > file. So I'm sending this followup to call attention to the bug report.
> >
> > Briefly, g++-4.2 is taking over 20 minutes to compile a source file from
> > python-qt3 (and I don't actually know whether it ever finishes), where
> > g++-4.1 takes under 2 minutes.
>
> please could you recheck with gcc-snapshot (and attach the
> preprocessed source)?
The latest gcc-snapshot seems quite a bit better, but still much slower than
g++-4.1:
frobnitz:/tmp/buildd/python-qt3-3.17.3/build-2.4/qt# time g++-4.1 -c -O2 -pipe -fPIC -g -Wall -W -D_REENTRANT -DQT_THREAD_SUPPORT -I. -I/usr/include/python2.5 -I/usr/share/qt3/mkspecs/default -I/usr/share/qt3/include -I/usr/X11R6/include -o sipqtpart0.o sipqtpart0.cpp
real 0m46.583s
user 0m43.527s
sys 0m1.052s
frobnitz:/tmp/buildd/python-qt3-3.17.3/build-2.4/qt# time g++-4.2 -c -O2 -pipe -fPIC -g -Wall -W -D_REENTRANT -DQT_THREAD_SUPPORT -I. -I/usr/include/python2.5 -I/usr/share/qt3/mkspecs/default -I/usr/share/qt3/include -I/usr/X11R6/include -o sipqtpart0.o sipqtpart0.cpp
real 58m56.571s
user 50m55.711s
sys 7m43.485s
frobnitz:/tmp/buildd/python-qt3-3.17.3/build-2.4/qt# time /usr/lib/gcc-snapshot/bin/g++ -c -O2 -pipe -fPIC -g -Wall -W -D_REENTRANT -DQT_THREAD_SUPPORT -I. -I/usr/include/python2.5 -I/usr/share/qt3/mkspecs/default -I/usr/share/qt3/include -I/usr/X11R6/include -o sipqtpart0.o sipqtpart0.cpp
In file included from /tmp/buildd/python-qt3-3.17.3/sip/qt/qimage.sip:139:
/usr/share/qt3/include/qimage.h: In member function 'bool QImageTextKeyLang::operator<(const QImageTextKeyLang&) const':
/usr/share/qt3/include/qimage.h:58: warning: suggest parentheses around && within ||
/tmp/buildd/python-qt3-3.17.3/sip/qt/qtabbar.sip: In function 'PyObject* meth_QTabBar_tabList(PyObject*, PyObject*)':
/tmp/buildd/python-qt3-3.17.3/sip/qt/qtabbar.sip:255: warning: suggest explicit braces to avoid ambiguous 'else'
real 8m47.002s
user 8m37.520s
sys 0m2.244s
I'll attach the preprocessed source using gcc-snapshot 20070811 in a separate
message.
--
Daniel Schepler
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