Merge pull request #1373 from rust-lang/pa-1.80.1

Add post for Rust 1.80.1

Author: pietroalbini

posts/2024-08-08-Rust-1.80.1.md

@@ -0,0 +1,56 @@
+---
+layout: post
+title: "Announcing Rust 1.80.1"
+author: The Rust Release Team
+release: true
+---
+
+The Rust team has published a new point release of Rust, 1.80.1. Rust is a
+programming language that is empowering everyone to build reliable and
+efficient software.
+
+If you have a previous version of Rust installed via rustup, getting Rust
+1.80.1 is as easy as:
+
+```
+rustup update stable
+```
+
+If you don't have it already, you can [get `rustup`][rustup] from the
+appropriate page on our website.
+
+[rustup]: https://www.rust-lang.org/install.html
+
+## What's in 1.80.1
+
+Rust 1.80.1 fixes two regressions that were recently reported.
+
+### Miscompilation when comparing floats
+
+In addition to the existing optimizations performed by LLVM, rustc is growing
+its own set of optimizations. Rust 1.78.0 added a new one, implementing ["jump
+threading"] (merging together two adjacent branches that perform the same
+comparison).
+
+The optimization was also enabled on branches checking for floating point
+equality, but it didn't implement the special rules needed for floats
+comparison (`NaN != NaN` and `0.0 == -0.0`). This caused the optimization to
+miscompile code performing those checks.
+
+Rust 1.80.1 addresses the problem by preventing the optimization from being
+applied to float comparisons, while retaining the optimization on other
+supported types.
+
+### False positives in the `dead_code` lint
+
+Rust 1.80.0 contained refactorings to the `dead_code` lint. We received
+multiple reports that the new lint implementation produces false positives, so
+we are reverting the changes in Rust 1.80.1. We'll continue to experiment on
+how to improve the accuracy of `dead_code` in future releases.
+
+## Contributors to 1.80.1
+
+Many people came together to create Rust 1.80.1. We couldn't have done it
+without all of you. [Thanks!](https://thanks.rust-lang.org/rust/1.80.1/)
+
+["jump threading"]: https://en.wikipedia.org/wiki/Jump_threading