Re: C++ compile time (again)

[Karel Gardas <kgardas at objectsecurity dot com>]

On Tue, 17 Jun 2003, Diego Novillo wrote:

> On Tue, 2003-06-17 at 09:35, Karel Gardas wrote:
>
> > Options used to compile all cc files are:
> >
> > -I../include  -Wall -fpermissive   -DPIC -fPIC  -c
> >
> > times (user only) for cd mico/orb; time make are:
> >
> > gcc2.95.4: 6m4s
> > gcc3.4:    9m24s
> > gcc3.5:   11m17s
> >
> >
> > Anything else what should I test for you?
> >
> You haven't used optimization?  If not, then timings are not including
> the SSA transformations.  Could you add that?

Sure! I have tried both -O1 and -O2 with both gcc3.4 and 3.5. In all four
options compilation fails with:

c++  -I../include  -O2  -Wall -fpermissive   -DPIC -fPIC  -c fixed.cc -o
fixed.pic.o
/usr/include/bits/mathinline.h: In member function `void
   FixedBase::adjust(unsigned char)':
/usr/include/bits/mathinline.h:429: error: can't find a register in class
`
   FP_TOP_REG' while reloading `asm'
make: *** [fixed.pic.o] Error 1


which is IMHO some problem in gcc - since the problematic header file is
from glibc2.2.5 distro...

Anyway, some part of MICO is compilable (till this failure) and so time
comparison looks:

gcc3.4 -O1: 4m4.540s
gcc3.4 -O2: 4m51.580s

gcc3.5 -O1: 7m22.990s
gcc3.5 -O2: 6m38.970s

Yes, that's not error -O1 is really slower than -O2. In addition if you
will try it, you will find that on typecode.cc file, gcc3.5 + -O1 requires
a lot more memory to compile this file. - peak value was about 410MB -
while standard (for recent gcc with mem hack on) is about 210MB.

This is on linux with 512MB real mem + 512MB swap.

Cheers,

Karel
--
Karel Gardas                  kgardas@objectsecurity.com
ObjectSecurity Ltd.           http://www.objectsecurity.com