I also think that vectorizers and compilers can detect parallel memory adds/moves/subs and without that, many do not take time to provide adequate hints to the

I also think that vectorizers and compilers can detect parallel memory adds/moves/subs and without that, many do not take time to provide adequate hints to the compiler about it. Some people have vectorized successfully with C, even with all the hacks/pointers/union/opaque business. It requires careful programming, for sure. The ffmpeg cases are super good examples of how compiler misses happen, and how to optimize for full throughput in those cases. Worth a look for all compiler engineers.