Interesting. The one time I ended up writing assembly was because of SIMD. I was speaking about it recently and had forgotten it was because SIMD instructions, so nice to be reminded. However, that one time, I also ended up finding the right syntactic sugar, to get the compiler to do it right. If I remember right it was all down to aliasing. I had to convince the compiler the data wasn't going to be accessed any other place. It wasn't working that out itself, so it didn't know it could use the SIMD instruction I was. Once I found this and the right non-standard extra key words, the compiler would do it right. So I ended removing the assembly I had written.