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 35283
BUG=
Review URL: https://codereview.chromium.org/1324453007
Cr-Commit-Position: refs/heads/master@{#30597}
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}
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
Review URL: https://codereview.chromium.org/1303033012
Cr-Commit-Position: refs/heads/master@{#30587}
