A very quick example of why big -O3 gcc optimizations are a bad thing?
my /etc/make.conf has
USA_RESIDENT=NO
CFLAGS=-O3 -pipe -mcpu=pentiumpro -march=pentiumpro -fomit-frame-pointer
NOPROFILE=true
(NOPROFILE=true because profiled libraries fail to build with no frame pointer)
now, cd /usr/ports/net/kicq; make install
bender:~> kicq
Segmentation fault(core dumped)
bender:~>
kicq is broken, and segfaults. Infact it dumps core with a problem in the
QT library with QString::find(). But why? due to -O3 optimizations, kicq
does something stupid and passes an invalid value/pointer to a QString
causing it to dump core. I haven't bothered to go into this in detail
(compiling kicq AND qt with -g to see whats happening). Why bother ?
No optimizations fixes this.
Mind you, there are a few other ports that are like this also, it appears
to be a bug with gcc 2.96.2's C++ compiler. It was always fine in gcc
2.7.2.
Make world runs perfectly with my -O3 and -mcpu=pentiumpro optimizations,
however. Its just a few ports that happen to be in C++. So gcc definately
has problems there.
Hopefully this will show why you should be real cautious, and the second
you have problems with a program dumping core recompile WITHOUT
optmizations, or ONLY use -O, no higher.
--
Martin Minkus aka DiSKiLLeR
Email: [EMAIL PROTECTED] Web: http://www.diskiller.net
I live in a world of paradox... my willingness to destroy is
your chance for improvement, my hate is your faith, my failure
is your victory - a victory that won't last.
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