btw, the current dev version of clang is broken for months. It crashes on a failed assertion when I'm trying to compile erlang or mplayer+ffmpeg. It also failed to build racket - the resulting binary eats all the memory and dies.) Gcc does the job. So, it seems that while running after C++ features they ruined the plain old C.)
LLVM and Clang have nightly buildbots that check for regressions. They are quite fastidiously maintained. The project would really appreciate your help and you can do so by submitting a bug report with steps to reproduce and build artifacts. The bugfix will contain a test case, likely a minimal reduction of your repro, that will be run in the buildbots to make sure that you never see the same problem again.
And I do not believe that they have sacrificed anything to support both C and C++ (including partial support for their '11 variants). The codebase is abstracted away from the C/C++ differences where it makes sense. It is an impressively comprehensible compiler!
