feat: add global value numbering pass by arnoox · Pull Request #37 · arnoox/herkos

arnoox · 2026-03-27T08:18:39Z

Summary

Adds gvn as a new post-lowering optimizer pass
Extends local CSE across basic block boundaries via dominator-tree traversal: a pure computation available in a dominating block is reused in dominated blocks instead of recomputed
Runs after local_cse so GVN only handles residual cross-block redundancies

Pipeline position

... → local_cse → gvn → dead_instrs → branch_fold → dead_instrs → ...

Test plan

cargo test -p herkos-core --lib — 214 tests pass (6 new gvn tests)
cargo clippy — clean
cargo fmt --check

Stack

This is PR F3 of 4 in the optimizer split. Stacked on PR F2 (pr-f2/local-cse → #36).

PR	Pass	Status
F1	`branch_fold`	#35
F2	`local_cse`	#36
F3 (this)	`gvn`	⬅
F4	`licm`	pending

🤖 Generated with Claude Code

Adds `gvn` as a new post-lowering optimizer pass. Extends local CSE across basic block boundaries using dominator-tree traversal: a pure computation available in a dominating block is reused in dominated blocks instead of being recomputed. Runs after local_cse so GVN handles only residual cross-block redundancies. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/herkos-core/src/optimizer/gvn.rs

…te_rpo documentation with examples

arnoox mentioned this pull request Mar 27, 2026

feat: add loop invariant code motion pass #38

Merged

3 tasks

arnoox changed the base branch from pr-f2/local-cse to main March 27, 2026 09:36

Merge branch 'main' of https://github.com/arnoox/herkos into pr-f3/gvn

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