Possible 3x improvement on addition?

[karalabe]

Hey all, @Bren2010. We've received a downstream PR against go-ethereum that supposedly improves addition by a factor of 3. Would you be interested in maybe reviewing and upstreaming this PR here? ethereum/go-ethereum#21515

[Bren2010]

This optimization only helps when you need to output the final result, which I wouldn't think is a major place you're spending time. Because while you're doing your curve math, you can leave the intermediate results non-affine.

Is it the case that you're spending a lot of time outputting points? Assigning to @armfazh for more in-depth review if so