How Rust 1.64 Became 10-20% Faster On Windows?

If you are a Rust developer you have most likely celebrated the news that the version 1.64 released on 22/09/2022 is 10-20% faster on Windows.

It is one of the most important changes in that release aside of stabilization of some APIs.

But how one merge request made it possible to account to such a performance improvement?

The person behind the merge request is Rémy Rakic aka lqd (pronounced liquid), a French software engineer regularly contributing changes to the Rust compiler.