perf: UseMultilineReverseSuffix uses DFA instead of PikeVM (#99) #100
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Replace O(n*m) PikeVM verification with O(n) DFA verification for multiline suffix patterns like (?m)^/.*\.php Changes: - MultilineReverseSuffixSearcher.forwardDFA replaces pikevm field - Uses lazy.DFA.SearchAtAnchored() for anchored matching - lazy.CompileWithConfig() creates forward DFA with proper config Performance: - No-match cases: 10-131x faster (microseconds vs milliseconds) - Large input (6MB): expected 10-30x improvement Research showed Rust hybrid DFA also uses DFA (not per-state acceleration) for verification - this is the correct approach.
Benchmark ComparisonComparing Summary:
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Summary
Replace O(n*m) PikeVM verification with O(n) DFA verification for multiline suffix patterns.
Issue: #99 (Rust regex 84x faster on
(?m)^/.*\.php)Root Cause (from research)
The 84x performance gap was NOT due to missing DFA state acceleration. Research revealed:
dfa/lazy/MultilineReverseSuffixSearcherused PikeVM (O(n*m)) instead of DFA (O(n))Changes
MultilineReverseSuffixSearcher.forwardDFAreplacespikevmfieldlazy.DFA.SearchAtAnchored()for linear-time anchored matchinglazy.CompileWithConfig()creates forward DFA with proper configPerformance
Testing
Technical Details
Research document:
docs/dev/research/DFA_STATE_ACCELERATION_RESEARCH.mdKey insight from Rust code (
hybrid/search.rs):Fixes #99 (Phase 1)