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Joe Tsai 5baf60d472 bytes, strings: optimize Trim for single byte cutsets
Using the latest version of all modules known by the module proxy,
we determine that for all Trim usages (and related functionality):
* 76.6% have cutsets of len=1, and
* 13.4% have cutsets of len=2.

Given that a vast majority of usages only have a cutset of len=1,
we should more heavily optimize for that situation.
Previously, there was some optimization for cutsets of len=1,
but it's within the internal makeCutsetFunc function.
This is sub-optimal as it incurs an allocation in makeCutsetFunc
for the closure over that single byte.

This CL removes special-casing of one-byte cutsets from makeCutsetFunc
and instead distributes it directly in Trim, TrimRight, and TrimLeft.
Whether we should distribute the entire ASCII cutset logic into Trim
is a future CL that should be discussed and handled separately.
The evidence for multibyte cutsets is not as obviously compelling.

name                old time/op  new time/op  delta
bytes/TrimByte-4    84.1ns ± 2%   7.5ns ± 1%  -91.10%  (p=0.000 n=9+7)
strings/TrimByte-4  86.2ns ± 3%   8.3ns ± 1%  -90.33%  (p=0.000 n=9+10)

Fixes #46446

Change-Id: Ia0e31a8384c3ce111ae35465605bcec45df2ebec
Reviewed-on: https://go-review.googlesource.com/c/go/+/323318
Trust: Joe Tsai <joetsai@digital-static.net>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
2021-08-25 19:29:15 +00:00
.github .github: add link to questions in ISSUE_TEMPLATE 2020-01-06 17:05:31 +00:00
api net: reduce allocations for UDP send/recv on Windows 2021-08-16 23:57:10 +00:00
doc spec: add example for method value in case of embedded method 2021-08-23 17:29:25 +00:00
lib/time lib/time: fix RFC 6557 url 2021-08-15 02:18:46 +00:00
misc cmd/cgo: fix unused parameter warnings in generated _cgo_main.c 2021-08-16 23:03:03 +00:00
src bytes, strings: optimize Trim for single byte cutsets 2021-08-25 19:29:15 +00:00
test cmd/compile: fix function contains no TParam in generic function 2021-08-25 19:06:16 +00:00
.gitattributes all: treat all files as binary, but check in .bat with CRLF 2020-06-08 15:31:43 +00:00
.gitignore internal/buildcfg: move build configuration out of cmd/internal/objabi 2021-04-16 19:20:53 +00:00
AUTHORS A+C: update name 2021-06-01 17:08:12 +00:00
codereview.cfg codereview.cfg: add codereview.cfg for master branch 2021-02-19 18:44:53 +00:00
CONTRIBUTING.md
CONTRIBUTORS CONTRIBUTORS: update for the Go 1.17 release 2021-08-12 17:43:16 +00:00
LICENSE
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README.md README: pull gopher image from website 2021-02-16 18:25:10 +00:00
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