Commit Graph

3 Commits

Author SHA1 Message Date
Tim Cooper c6e8426386 all: fix typo in RuneSelf, runeSelf comments
Fixes #36396

Change-Id: I52190f450fa9ac52fbf4ecdc814e954dc29029cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/213377
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-01-06 02:46:02 +00:00
Martin Möhrmann b9a59d9f2e cmd/compile: optimize len([]rune(string))
Adds a new runtime function to count runes in a string.
Modifies the compiler to detect the pattern len([]rune(string))
and replaces it with the new rune counting runtime function.

RuneCount/lenruneslice/ASCII                  27.8ns ± 2%  14.5ns ± 3%  -47.70%  (p=0.000 n=10+10)
RuneCount/lenruneslice/Japanese                126ns ± 2%    60ns ± 2%  -52.03%  (p=0.000 n=10+10)
RuneCount/lenruneslice/MixedLength             104ns ± 2%    50ns ± 1%  -51.71%  (p=0.000 n=10+9)

Fixes #24923

Change-Id: Ie9c7e7391a4e2cca675c5cdcc1e5ce7d523948b9
Reviewed-on: https://go-review.googlesource.com/108985
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-05-06 05:31:01 +00:00
Martin Möhrmann d295174030 runtime: speed up non-ASCII rune decoding
Copies utf8 constants and EncodeRune implementation from unicode/utf8.

Adds a new decoderune implementation that is used by the compiler
in code generated for ranging over strings. It does not handle
ASCII runes since these are handled directly before calls to decoderune.

The DecodeRuneInString implementation from unicode/utf8 is not used
since it uses a lookup table that would increase the use of cpu caches.

Adds more tests that check decoding of valid and invalid utf8 sequences.

name                              old time/op  new time/op  delta
RuneIterate/range2/ASCII-4        7.45ns ± 2%  7.45ns ± 1%     ~     (p=0.634 n=16+16)
RuneIterate/range2/Japanese-4     53.5ns ± 1%  49.2ns ± 2%   -8.03%  (p=0.000 n=20+20)
RuneIterate/range2/MixedLength-4  46.3ns ± 1%  41.0ns ± 2%  -11.57%  (p=0.000 n=20+20)

new:
"".decoderune t=1 size=423 args=0x28 locals=0x0
old:
"".charntorune t=1 size=666 args=0x28 locals=0x0

Change-Id: I1df1fdb385bb9ea5e5e71b8818ea2bf5ce62de52
Reviewed-on: https://go-review.googlesource.com/28490
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-17 11:25:22 +00:00