Implement LLVM-backed MC/DC instrumentation in the compiler

Meeting proposal info

• Title: Discuss technical aspects of MC/DC coverage instrumentation in the compiler
• Type: technical

Summary

MC/DC Instrumentation Design Document

TL;DR: MC/DC coverage is an essential requirement for the high-integrity software industry. The document proposes an implementation design for the MC/DCcoverage instrumentation that essentially lives between THIR and MIR.
Additionally, it mentions the application of the MC/DC coverage criterion to the principle of Pattern Matching, and the pain points that will have to be dealt with.

About this issue

This issue corresponds to a meeting proposal for the compiler team
steering meeting. It corresponds to a possible topic of
discussion. You can read more about the steering meeting procedure
here.

Comment policy

These issues are meant to be used as an "announcements channel"
regarding the proposal, and not as a place to discuss the technical
details. Feel free to subscribe to updates. We'll post comments when
reviewing the proposal in meetings or making a scheduling decision.
In the meantime, if you have questions or ideas, ping the proposers
on Zulip #project-goals/2026-workshop > mcdc-support.

Start with the linked MC/DC Instrumentation Design Document and the compiler-team steering-meeting procedure. This issue names no source files, tests, or implementation entry point; it is a meeting proposal, so completion is a reviewed discussion and scheduling decision rather than a patch.