There's definitely improvements being made to LLVM to automatically parallelize code (esp unrolling loops) to SIMD.

I haven't personally tried it, but would love for it to match the code quality of hand-cranked assembly... writing it is tedious, error prone, but you do get control over when you preload the cache, the stack, and you can do really cool things with the CPP and macros to "manually inline" things. :-)

And who doesn't like writing a good 'ol fashioned jump table?!