Value numbering

▤ Summary

This article explains value numbering as a compiler optimization technique that finds and reuses equivalent SSA instructions. It walks through local value numbering first, then extends the idea to global value numbering using dominator relationships in control-flow graphs. It also covers purity constraints, load/store forwarding, and the complications introduced by loops and phis. The post closes by comparing several implementation styles and noting where JIT compilers can benefit from the same approach.

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