Because your looking at 4-5 variants to cover standard compliant c++, SSE2, AVX, AVX2 and NEON. Also the vector specific code takes up 70-80% of the functions I'm looking at optimising so it would be far cleaner just to have 5 functions and then keeping them in sync is a pain.
Also with the path I'm going down at the moment it would be easy to add AVX-512 support when intel release skylake in 2015. It would also be easier to add support for any strange platforms that someone wants to use (GPUs, PowerPC in an old mac, MIPS on a PS3, Itanium, Mill if it gets released).
Also with the path I'm going down at the moment it would be easy to add AVX-512 support when intel release skylake in 2015. It would also be easier to add support for any strange platforms that someone wants to use (GPUs, PowerPC in an old mac, MIPS on a PS3, Itanium, Mill if it gets released).