Performance wise I've seen some good results from Clang SVN in the last few months. Not universally faster (or slower) than GCC or ICC, but I have seen (important, useful) cases where code was 30-50% faster compiled with Clang than anything else I tried. (I also saw cases that had terrible performance, and occasionally miscompiled code, though mostly it was +-10% of GCC).
I can't say I understand why anyone would care too much about compilation speed, though - GCC+ccache is about as fast as Clang+ccache, as the primary bottleneck is disk throughput.
> GCC+ccache is about as fast as Clang+ccache, as the primary bottleneck is disk throughput.
I often compile code that has not been compiled before. For example when using MacPorts.
Never underestimate how much people like speed. I never thought SVN was slow or that I needed speed, until I tried git and realized I could not even consider using something slower.
That's one of the main reasons I like Go. It's been explicitly designed to enable fast compilation, and even at this early stage its compilers are very fast.
Even if you're compiling code that you work on all the time changing a compile flag can invalidate all your ccache files. Having to wait 10 seconds instead of 30 for the new compile to finish can make a big difference when you want to be able to test changes quickly.
I can't say I understand why anyone would care too much about compilation speed, though - GCC+ccache is about as fast as Clang+ccache, as the primary bottleneck is disk throughput.