[swatcoder]

This isn’t an optimization you should consider without insight into your actual bottlenecks, but compilers can be even more aggressive with code that’s strictly local to one translation unit (i.e. inside an anonymous namespace in a cpp file) than they typically would be when seeing an inline hint elsewhere.

It’s not quite the same.

Plus, another benefit of duplication is that you can more freely hand-tune your implementation once you’ve decided its private. Memory alignment, pointer aliasing hints, clever loop structures, SSE stuff, etc can all be used more freely when you know nothing else needs to use this version.

The article is a good teaser around how unintuitive optimization can be, but it only scratches the surface.