Very interesting!
I wonder how Teju Jaguá compares. I don't see it in the C++ benchmark repo you linked and whose graph you included.
I have contributed an implementation in Rust :) https://crates.io/crates/teju it includes benchmarks which compare it vs Ryu and vs Rust's stdlib, and the readme shows a graph with some test cases. It's quite easy to run if you're interested!
Any ideas why Rust’s stdlib hasn’t adopted faster implementations?
I am not sure how it compares but I did use one idea from Cassio's talk on Teju:
> A more interesting improvement comes from a talk by Cassio Neri Fast Conversion From Floating Point Numbers. In Schubfach, we look at four candidate numbers. The first two, of which at most one is in the rounding interval, correspond to a larger decimal exponent. The other two, of which at least one is in the rounding interval, correspond to the smaller exponent. Cassio’s insight is that we can directly construct a single candidate from the upper bound in the first case.