Compiling c++ template is very slow.

I tried to use c++ template to generate code for a personal project, but found that the compilation time needed with g++ is much slower(exponentially) than with clang++. This is a code snippet for testing purpose: #include template struct v : v, v { static int constexpr m = a; static int

Please update the documentation about source tree.

I read about the internals of GCC from GCC online documentation about the source tree, and found some source directories are missing from the documentation. For example in the top directory: libbacktrace libcc1 libcilkrts libhsail-rt libmpx liboffloadmic libsantizer libvtv and in the gcc direct