perf: linearize CollectNonLeafSubtrees, defer per-node Render#39
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CollectNonLeafSubtrees called CountNodes per node — O(n^2) worst case (bounded only by the 50 000-node lift gate, so ~2.5e9 ops). Compute subtree size via post-order summation in a single walk. Defer Render until a hash bucket actually contains another node, back-filling the existing entry on the second occurrence. Single-occurrence entries never render. Closes audit finding lifting-passes-11. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
CollectNonLeafSubtreescalledCountNodesper node — O(n²) worst case (bounded only by the 50 000-node lift gate, ~2.5e9 ops). Compute subtree size via post-order summation in a single walk.Renderuntil a hash bucket actually contains another node, back-filling the existing entry on the second occurrence. Single-occurrence entries never render.lifting-passes-11.Test plan
RepeatedSubexprLifter,ArithmeticAtomLifter,Simplifiertests (125 total) pass locally.🤖 Generated with Claude Code