Fair enough.

I had some trouble using the ubuntu 13 packages for gdc, so i downloaded it from the gdc project binaries as of the latest available there, as recommended by the readme.

Using that to compile warp with gdc with the flags it suggests (-release is not recognized by gdc, -O3 is), i get a warp that works.

For including every file in /usr/include/boost/*.hpp in one .cc file (which produces roughly 16 megabytes of C++ code), we get:

[dannyb@mainserver 12:40:56] ~ :) $ time gcc -E e.cc >f

In file included from e.cc:101:0:
/usr/include/boost/spirit.hpp:18:4: warning: #warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp" [-Wcpp]
# warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp"
^

gcc -E e.cc > f 3.18s user 0.25s system 97% cpu 3.528 total

[dannyb@mainserver 12:40:51] ~ :) $ time clang -E e.cc >f

In file included from e.cc:101:
/usr/include/boost/spirit.hpp:18:4: warning: "This header is deprecated. Please use: boost/spirit/include/classic.hpp" [-W#warnings]
# warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp"
^
1 warning generated.

clang -E e.cc > f 1.42s user 0.14s system 93% cpu 1.657 total

[dannyb@mainserver 12:40:33] ~ :( $ time ./warp/fwarpdrive_gcc4_8_1 -I/usr/include -I/usr/include/c++/4.8 -I/usr/include/x86_64-linux-gnu/c++/4.8 -I/usr/include/x86_64-linux-gnu -I/usr/lib/gcc/x86_64-linux-gnu/4.8/include/ -I/usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed/ e.cc >f

cla/usr/include/boost/spirit.hpp(18) : warning: "This header is deprecated. Please use: boost/spirit/include/classic.hpp"

./warp/fwarpdrive_gcc4_8_1 -I/usr/include -I/usr/include/c++/4.8 e.cc 2.88s user 0.06s system 95% cpu 3.080 total

I've repeated these timings 10 times, and they are within 0.5% of these numbers each time.

I've also tried this on a large C++ project i have, that generates about 200 meg of preprocessed source (that i can't share, sadly) and got similar relative timings. I also tried it on some smaller projects.
Based on data i have so far, clang blows warp out of the water by a factor of 2 in most cases i've tried it.

The above tests include stdout IO, but the relative numbers are the same without it:

[dannyb@mainserver 12:48:24] ~ :( $ time gcc -E e.cc -o f

In file included from e.cc:101:0:
/usr/include/boost/spirit.hpp:18:4: warning: #warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp" [-Wcpp]
# warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp"
^

gcc -E e.cc -o f 3.14s user 0.27s system 99% cpu 3.418 total

[dannyb@mainserver 12:48:33] ~ :) $ time clang -E e.cc -o f

In file included from e.cc:101:
/usr/include/boost/spirit.hpp:18:4: warning: "This header is deprecated. Please use: boost/spirit/include/classic.hpp" [-W#warnings]
# warning "This header is deprecated. Please use: boost/spirit/include/classic.hpp"
^
1 warning generated.

clang -E e.cc -o f 1.41s user 0.13s system 94% cpu 1.631 total

[dannyb@mainserver 12:48:40] ~ :) $

(I reordered this one to make the timings in the same order as they were before)

[dannyb@mainserver 12:47:38] ~ :( $ time ./warp/fwarpdrive_gcc4_8_1 -o f -I/usr/include -I/usr/include/c++/4.8 -I/usr/include/x86_64-linux-gnu/c++/4.8 -I/usr/include/x86_64-linux-gnu -I/usr/lib/gcc/x86_64-linux-gnu/4.8/include/ -I/usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed/ e.cc

/usr/include/boost/spirit.hpp(18) : warning: "This header is deprecated. Please use: boost/spirit/include/classic.hpp"

./warp/fwarpdrive_gcc4_8_1 -o f -I/usr/include -I/usr/include/c++/4.8 e.c 2.93s user 0.02s system 99% cpu 2.953 total

Warp is definitely faster than GCC, though.