Rust 1.98.0 stabilizes algebraic floating-point methods and buffered integer formatting

Sources: Rust 1.98.0 release announcement, HN discussion
Summary: The algebraic methods on f32 and f64 let the compiler reorder and vectorize arithmetic the way -ffast-math does elsewhere, and the release states they are non-deterministic because the compiler picks the optimizations, while never causing undefined behavior. format_into with a NumBuffer bypasses most of the dynamic dispatch in write! formatting, and the release points at the itoa benchmark showing parity, so it can replace that dependency. The release also makes the fixed ManuallyDrop and Box interaction a documented stable guarantee rather than a 1.96.0 bug fix.
Why it matters: Fast-math style float optimization is now reachable from stable Rust without giving up the guarantee that it cannot cause undefined behavior.