https://discourse.llvm.org/t/the-preview-of-fbounds-safety-i...:

“-fbounds-safety is a language extension to enforce a strong bounds safety guarantee for C. Here is our original RFC.

We are thrilled to announce that the preview implementation of -fbounds-safety is publicly available at this fork of llvm-project. Please note that we are still actively working on incrementally open-sourcing this feature in the llvm.org/llvm-project . To date, we have landed only a small subset of our implementation, and the feature is not yet available for use there. However, the preview does contain the working feature. Here is a quick instruction on how to adopt it.”

“This fork” is https://github.com/swiftlang/llvm-project/tree/stable/202407..., Apple’s fork of LLVM. That branch is from a year ago.

I don’t know whether there’s a newer publicly available version.

There is a GSoC 2026 opportunity on upstreaming this into mainline LLVM (https://discourse.llvm.org/t/gsoc-2026-participating-in-upst...)