[cfe-dev] libc++ clean-up

["C. Bergström"]

Hi

Would patches for cleaning up unnecessary #include for libc++ be 
accepted? In general it seems like it has followed the rather poorly 
designed GNU STL rather than being more strict.

A simple preprocessed hello world which only #include <iostream>

CC -E hello.cxx -std=c++11  > hello-libcxx.e.cxx

du -sh *.e.cxx
532K    hello-stdcxx.e.cxx
1.3M    hello-libcxx.e.cxx

The effects of this cascade into being a measurable performance 
difference later on in the compiler. (My numbers may not be exactly llvm 
upstream though - ymmv) Basically the Module size and other things are 
larger as a result.

Thoughts/feedback?