>> Also, is there any significant difference in bootstrap times?
> 
> I haven't actually measured, but subjectively bootstrap does seem to
> take longer.
I tried this out of curiosity. The numbers below are the bootstrap times on 
a 64bit 2.6.28 Linux system (Core 2 E8400), building single threaded with   
--enable-languages=c,c++ --disable-multilib

Regular gcc:

real    59m6.914s
user    53m53.702s
sys     3m24.073s

gcc-in-cxx:

real    68m15.366s
user    61m32.255s
sys     4m24.481s

Of course the bootstrap times are not that useful themselves, as they 
compare two quite different compilation tasks (one C, one C++). To get a 
better idea about the different compiler speeds, I compiled some random 
(reasonably complex) C++ code I had at hand, and compared the compile times.

Regular gcc:

real    0m30.478s
user    0m27.842s
sys     0m1.888s

gcc-in-cxx:

real    0m35.926s
user    0m34.386s
sys     0m1.208s

Again the comparison is not 100% fair ("regular gcc" is current mainline, 
while the gcc-in-cxx branch is older), but apparently the C++ version is 
quite a bit slower.

Admittedly gcc-in-cxx just recently managed to bootstrap at all, so perhaps 
performance comparisons are a bit unfair. But I do not mean this as critique 
of gcc-in-cxx, I want to help improve it and to bring it to the same speed 
as regular mainline.
Is there any reasonably simple way to find out why the C++ version is 
slower? I can use something like oprofile, of course, but I thought gcc can 
somehow give statistics about its internal times, which might be more useful 
for a first approximation.

Thomas



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