d57c6748c4
On the BMW scene, this gives roughly a 10% speedup overall with clang/gcc, and 30% speedup with visual studio (2008). It turns out visual studio was optimizing the existing code quite poorly compared to pretty good autovectorization by clang/gcc, but hand written SSE code also gives a smaller speed boost there. This code isn't enabled when using the hair minimum width feature yet, need to make that work with the SSE code still.