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machenbach authored
Revert of Speedup stringsearch for two byte strings (patchset #3 id:40001 of https://codereview.chromium.org/1303033012/ ) Reason for revert: [Sheriff] Breaks fuzzer and msan: http://build.chromium.org/p/client.v8/builders/V8%20Fuzzer/builds/4773 Repro with: tools/fuzz-harness.sh out/Debug/d8 (in a ninja Debug build) Msan: http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/builds/4097 Original issue's description: > Speedup stringsearch for two byte strings > > Uses the lower byte with memchr which is > significantly faster than a naive compare > > Performance difference with bench (http://hastebin.com/xuxexataso.js): > > old new > > single character single character > Κ found at 922 Κ found at 922 > 3324 616 > ㎡ found at 13217 ㎡ found at 13217 > 42366 4931 > က found at 4096 က found at 4096 > 13369 9836 > found at 65280 found at 65280 > 207472 36149 > ᆬ found at 65445 ᆬ found at 65445 > 209344 36666 > found at 8197 found at 8197 > 26731 11757 > 倂 found at 20482 倂 found at 20482 > 66071 17193 > > linear search linear search > ΚΛ found at 922 ΚΛ found at 922 > 4112 504 > ㎡㎢ found at 13217 ㎡㎢ found at 13217 > 55105 5119 > ᆬᆭ found at 65445 ᆬᆭ found at 65445 > 268016 35496 > > linear + bmh search linear + bmh search > ΚΛΜΝΞΟΠΡ found at 922 ΚΛΜΝΞΟΠΡ found at 922 > 2897 522 > ᆬᆭᄃᄄᄅᆰᆱᆲ found at 65445 ᆬᆭᄃᄄᄅᆰᆱᆲ found at 65445 > 167687 158465 > > Committed: https://crrev.com/fced280f37588f8a232a414201276e053117e9ea > Cr-Commit-Position: refs/heads/master@{#30587} TBR=danno@chromium.org,mstarzinger@chromium.org,jkummerow@chromium.org,karl@skomski.com NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true Review URL: https://codereview.chromium.org/1331433002 Cr-Commit-Position: refs/heads/master@{#30588}
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