>> 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
