[kixelated]

Summary

Plans two m4 follow-ups of the subset-compiler report (moq-dev/rust2#615):

• quest/m4/tpde.md: bench TPDE, a fast O0 code generator for LLVM IR, on moq once -Zllvm-tpde (rust-lang/rust#164108) reaches a nightly the bench can pin. It waits on rust-lang/rust under ## Waiting, and targets the LLVM share that report measured: 21% of a clean build, 28% of a non-incremental edit (36% with IR building, which TPDE does not replace).
• quest/m4/bench-moq-pin.md: bump the build benchmark's moq pin past poll-first. At the current pin (f36c848) the hub edit rebuilds 8 crates, against 10 at main.

Decisions

• Decided with the maintainer on 2026-11-07: both join m4.

Choices made without asking

• Kept TPDE to one quest with a ## Waiting item, rather than a separate waiting quest for the nightly bump. Nightly variants compare against nightly in the same job, so bumping the nightly and adding the variant can land together.
• Quoted the non-incremental edit as 28% LLVM, with 36% including IR building, since TPDE replaces only emission.
• Ranked the pin bump above TPDE in m4's Required, since it is ready now.
• Recommended in the pin quest's Plan: merge moq main into a new spike/pure-crypto branch, so moq-pure-crypto keeps comparing the same tree.

Impact

• Public API: none.
• Quest tree: adds two quests to m4.

Models

Size: S
Implementer: Claude Code, claude-opus-5-5, high effort

(Written by Claude Opus 5.5 with high effort)

🤖 Generated with Claude Code

Review

Rewritten by quest review after each round.

• Reviewer: Codex, gpt-6.1-sol, medium effort
• Session: 01a1b455-4147-7c92-8203-4df8de5d96dd, round 1
• Head: ffaf7bd
• Base: origin/main at 258ba24
• Score: 10/10, The specified diff adds two research quests and their index links, with no actionable defects or changes to executable code or benchmark configuration.
• Findings: none

[pullfrog]

  ^{｜ Review this ➔}

[coderabbitai]

Warning

Review limit reached

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

Next included review available in 3 minutes.

Check out review usage here.

View limit details

Limit details: You’ve used the included review currently available.

Learn how review limits work.

Review configuration:

Run configuration

• Source mode: Auto
• Repository: Unavailable
• Branch: Unavailable
• File: No configuration file from this repository applied
• Commit: Unavailable
• Layers: Organization UI
• Review profile: CHILL
• Plan: Advanced
• Run ID: 8527b036-00ed-4075-9a2a-7dd2c5daf4ac

Commits

Reviewing files that changed from the base of the PR and between 6290f64 and 37767c6.

Files selected for processing: 3

• quest/m4/README.md
• quest/m4/bench-moq-pin.md
• quest/m4/tpde.md

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

Share

• X
• Mastodon
• Reddit
• LinkedIn

[kixelated]

Automated review by review (OpenAI)

Reviewed head ffaf7bd against base 258ba24.

No actionable defects found in this three-file planning change. Upstream rust-lang/rust#164108 is still open, so the explicit wait and shipped-toolchain smoke check are appropriate. Its try/only behavior matches the plan. The corpus currently has the cited f36c848 moq pin, a separate pure-crypto revision, and a separately pinned Nix comparison; keeping the corpus bump isolated preserves comparable measurements.

Implementation direction: explicitly configure a matched non-incremental baseline for the promised non-incremental hub-edit result. The ordinary edit-hub benchmark uses incremental compilation; copying Cranelift's scenario list alone does not establish that condition. Keep the normal incremental result separate, and report fallback counts and correctness/test outcomes alongside wall time and retired instructions. Refresh the pure-crypto comparison from the exact new baseline revision, not a moving main, so unrelated tree changes cannot explain its result.

Limits: GitHub-only static review of the complete diff, corpus definitions, benchmark documentation/workflow, and current upstream PR description/state. No build, benchmark, nightly smoke test, quest context, or validation executed. Reported build shares and rebuild counts were not independently measured. This COMMENT is not merge approval.