That may be true for simple operations on aligned buffers, and nice regular computation in general. Anything slightly complex will throw off the compiler and re

That may be true for simple operations on aligned buffers, and nice regular computation in general. Anything slightly complex will throw off the compiler and result in suboptimal performance in the best case, none or stupid vectorization the worst (and quite common) case. How do I know? We have some experience with vectorization in the team I work in (www.gromacs.org), our code has support for at about 10-12 SIMD instruction sets ;)