[NFC] cache repeated tree walks to avoid O(N^2) in optimizeTerminatingTails in CodeFolding#8602
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Changqing-JING wants to merge 7 commits intoWebAssembly:mainfrom
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[NFC] cache repeated tree walks to avoid O(N^2) in optimizeTerminatingTails in CodeFolding#8602Changqing-JING wants to merge 7 commits intoWebAssembly:mainfrom
Changqing-JING wants to merge 7 commits intoWebAssembly:mainfrom
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LGMT with some extra comments.
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Cache the result of getBranchTargets(getFunction()->body) in optimizeTerminatingTails so that recursive calls share the same computed set rather than each re-walking the entire function body. This avoids O(N²) behavior where N is the size of the function body, since the recursive calls previously each performed an O(N) tree walk. The cached targets are computed lazily on first need and passed through to the canMove overload that accepts pre-computed branch targets.
Benmark data
For the test case in #7319 (comment)
Main head:
time ./build/bin/wasm-opt --code-folding --enable-bulk-memory --enable-multivalue --enable-reference-types --enable-gc --enable-tail-call --enable-exception-handling -o /dev/null ./test3.wasm real 5m45.996s user 6m6.267s sys 0m3.798sThis PR:
time ./build/bin/wasm-opt --code-folding --enable-bulk-memory --enable-multivalue --enable-reference-types --enable-gc --enable-tail-call --enable-exception-handling -o /dev/null ./test3.wasm real 2m2.380s user 2m25.700s sys 0m2.449sBenchmark regression test
Test case: https://jetbrains.github.io/kotlinconf-app/73cbe24d7cf5a54d37ad.wasm
On main
On current PR