The Go programming language
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Jakub Ciolek d524e1eccd cmd/compile: on AMD64, turn x < 128 into x <= 127
x < 128 -> x <= 127
x >= 128 -> x > 127

This allows for shorter encoding as 127 fits into
a single-byte immediate.

archive/tar benchmark (Alder Lake 12600K)

name              old time/op    new time/op    delta
/Writer/USTAR-16    1.46µs ± 0%    1.32µs ± 0%  -9.43%  (p=0.008 n=5+5)
/Writer/GNU-16      1.85µs ± 1%    1.79µs ± 1%  -3.47%  (p=0.008 n=5+5)
/Writer/PAX-16      3.21µs ± 0%    3.11µs ± 2%  -2.96%  (p=0.008 n=5+5)
/Reader/USTAR-16    1.38µs ± 1%    1.37µs ± 0%    ~     (p=0.127 n=5+4)
/Reader/GNU-16       798ns ± 1%     800ns ± 2%    ~     (p=0.548 n=5+5)
/Reader/PAX-16      3.07µs ± 1%    3.00µs ± 0%  -2.35%  (p=0.008 n=5+5)
[Geo mean]          1.76µs         1.70µs       -3.15%

compilecmp:

hash/maphash
hash/maphash.(*Hash).Write 517 -> 510  (-1.35%)

runtime
runtime.traceReadCPU 1626 -> 1615  (-0.68%)

runtime [cmd/compile]
runtime.traceReadCPU 1626 -> 1615  (-0.68%)

math/rand/v2
type:.eq.[128]float32 65 -> 59  (-9.23%)

bytes
bytes.trimLeftUnicode 378 -> 373  (-1.32%)
bytes.IndexAny 1189 -> 1157  (-2.69%)
bytes.LastIndexAny 1256 -> 1239  (-1.35%)
bytes.lastIndexFunc 263 -> 261  (-0.76%)

strings
strings.FieldsFuncSeq.func1 411 -> 399  (-2.92%)
strings.EqualFold 625 -> 624  (-0.16%)
strings.trimLeftUnicode 248 -> 231  (-6.85%)

math/rand
type:.eq.[128]float32 65 -> 59  (-9.23%)

bytes [cmd/compile]
bytes.LastIndexAny 1256 -> 1239  (-1.35%)
bytes.lastIndexFunc 263 -> 261  (-0.76%)
bytes.trimLeftUnicode 378 -> 373  (-1.32%)
bytes.IndexAny 1189 -> 1157  (-2.69%)

regexp/syntax
regexp/syntax.(*parser).parseEscape 1113 -> 1102  (-0.99%)

math/rand/v2 [cmd/compile]
type:.eq.[128]float32 65 -> 59  (-9.23%)

strings [cmd/compile]
strings.EqualFold 625 -> 624  (-0.16%)
strings.FieldsFuncSeq.func1 411 -> 399  (-2.92%)
strings.trimLeftUnicode 248 -> 231  (-6.85%)

math/rand [cmd/compile]
type:.eq.[128]float32 65 -> 59  (-9.23%)

regexp
regexp.(*inputString).context 198 -> 197  (-0.51%)
regexp.(*inputBytes).context 221 -> 212  (-4.07%)

image/jpeg
image/jpeg.(*decoder).processDQT 500 -> 491  (-1.80%)

regexp/syntax [cmd/compile]
regexp/syntax.(*parser).parseEscape 1113 -> 1102  (-0.99%)

regexp [cmd/compile]
regexp.(*inputString).context 198 -> 197  (-0.51%)
regexp.(*inputBytes).context 221 -> 212  (-4.07%)

encoding/csv
encoding/csv.(*Writer).fieldNeedsQuotes 269 -> 266  (-1.12%)

cmd/vendor/golang.org/x/sys/unix
type:.eq.[131]struct 855 -> 823  (-3.74%)

vendor/golang.org/x/text/unicode/norm
vendor/golang.org/x/text/unicode/norm.nextDecomposed 4831 -> 4826  (-0.10%)
vendor/golang.org/x/text/unicode/norm.(*Iter).returnSlice 281 -> 275  (-2.14%)

vendor/golang.org/x/text/secure/bidirule
vendor/golang.org/x/text/secure/bidirule.init.0 85 -> 83  (-2.35%)

go/scanner
go/scanner.isDigit 100 -> 98  (-2.00%)
go/scanner.(*Scanner).next 431 -> 422  (-2.09%)
go/scanner.isLetter 142 -> 124  (-12.68%)

encoding/asn1
encoding/asn1.parseTagAndLength 1189 -> 1182  (-0.59%)
encoding/asn1.makeField 3481 -> 3463  (-0.52%)

text/scanner
text/scanner.(*Scanner).next 1242 -> 1236  (-0.48%)

archive/tar
archive/tar.isASCII 133 -> 127  (-4.51%)
archive/tar.(*Writer).writeRawFile 1206 -> 1198  (-0.66%)
archive/tar.(*Reader).readHeader.func1 9 -> 7  (-22.22%)
archive/tar.toASCII 393 -> 383  (-2.54%)
archive/tar.splitUSTARPath 405 -> 396  (-2.22%)
archive/tar.(*Writer).writePAXHeader.func1 627 -> 620  (-1.12%)

text/template
text/template.jsIsSpecial 59 -> 57  (-3.39%)

go/doc
go/doc.assumedPackageName 714 -> 701  (-1.82%)

vendor/golang.org/x/net/http/httpguts
vendor/golang.org/x/net/http/httpguts.headerValueContainsToken 965 -> 952  (-1.35%)
vendor/golang.org/x/net/http/httpguts.tokenEqual 280 -> 269  (-3.93%)
vendor/golang.org/x/net/http/httpguts.IsTokenRune 28 -> 26  (-7.14%)

net/mail
net/mail.isVchar 26 -> 24  (-7.69%)
net/mail.isAtext 106 -> 104  (-1.89%)
net/mail.(*Address).String 1084 -> 1052  (-2.95%)
net/mail.isQtext 39 -> 37  (-5.13%)
net/mail.isMultibyte 9 -> 7  (-22.22%)
net/mail.isDtext 45 -> 43  (-4.44%)
net/mail.(*addrParser).consumeQuotedString 1050 -> 1029  (-2.00%)
net/mail.quoteString 741 -> 714  (-3.64%)

cmd/internal/obj/s390x
cmd/internal/obj/s390x.preprocess 6405 -> 6393  (-0.19%)

cmd/internal/obj/x86
cmd/internal/obj/x86.toDisp8 303 -> 301  (-0.66%)

fmt [cmd/compile]
fmt.Fprintf 4726 -> 4662  (-1.35%)

go/scanner [cmd/compile]
go/scanner.(*Scanner).next 431 -> 422  (-2.09%)
go/scanner.isLetter 142 -> 124  (-12.68%)
go/scanner.isDigit 100 -> 98  (-2.00%)

cmd/compile/internal/syntax
cmd/compile/internal/syntax.(*source).nextch 879 -> 847  (-3.64%)

cmd/vendor/golang.org/x/mod/module
cmd/vendor/golang.org/x/mod/module.checkElem 1253 -> 1235  (-1.44%)
cmd/vendor/golang.org/x/mod/module.escapeString 519 -> 517  (-0.39%)

go/doc [cmd/compile]
go/doc.assumedPackageName 714 -> 701  (-1.82%)

cmd/compile/internal/syntax [cmd/compile]
cmd/compile/internal/syntax.(*scanner).escape 1965 -> 1933  (-1.63%)
cmd/compile/internal/syntax.(*scanner).next 8975 -> 8847  (-1.43%)

cmd/internal/obj/s390x [cmd/compile]
cmd/internal/obj/s390x.preprocess 6405 -> 6393  (-0.19%)

cmd/internal/obj/x86 [cmd/compile]
cmd/internal/obj/x86.toDisp8 303 -> 301  (-0.66%)

cmd/internal/gcprog
cmd/internal/gcprog.(*Writer).Repeat 688 -> 677  (-1.60%)
cmd/internal/gcprog.(*Writer).varint 442 -> 439  (-0.68%)

cmd/compile/internal/ir
cmd/compile/internal/ir.splitPkg 331 -> 325  (-1.81%)

cmd/compile/internal/ir [cmd/compile]
cmd/compile/internal/ir.splitPkg 331 -> 325  (-1.81%)

net/http
net/http.containsDotDot.FieldsFuncSeq.func1 411 -> 399  (-2.92%)
net/http.isNotToken 33 -> 30  (-9.09%)
net/http.containsDotDot 606 -> 588  (-2.97%)
net/http.isCookieNameValid 197 -> 191  (-3.05%)
net/http.parsePattern 4330 -> 4317  (-0.30%)
net/http.ParseCookie 1099 -> 1096  (-0.27%)
net/http.validMethod 197 -> 187  (-5.08%)

cmd/vendor/golang.org/x/text/unicode/norm
cmd/vendor/golang.org/x/text/unicode/norm.(*Iter).returnSlice 281 -> 275  (-2.14%)
cmd/vendor/golang.org/x/text/unicode/norm.nextDecomposed 4831 -> 4826  (-0.10%)

net/http/cookiejar
net/http/cookiejar.encode 1936 -> 1918  (-0.93%)

expvar
expvar.appendJSONQuote 972 -> 965  (-0.72%)

cmd/cgo/internal/test
cmd/cgo/internal/test.stack128 116 -> 114  (-1.72%)

cmd/vendor/rsc.io/markdown
cmd/vendor/rsc.io/markdown.newATXHeading 1637 -> 1628  (-0.55%)
cmd/vendor/rsc.io/markdown.isUnicodePunct 197 -> 179  (-9.14%)

Change-Id: I578bdf42ef229d687d526e378d697ced51e1880c
Reviewed-on: https://go-review.googlesource.com/c/go/+/639935
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
2025-02-16 07:23:13 -08:00
.github .github: update language change proposal template 2024-08-08 19:02:29 +00:00
api os: add Root.Chown 2025-02-13 15:29:56 -08:00
doc doc/godebug: mention GODEBUG=fips140 2025-02-14 15:54:46 -08:00
lib lib/time: build with Ubuntu backward compatibility options 2025-02-06 17:10:15 -08:00
misc misc/wasm: move wasm runtime files to lib/wasm 2024-08-30 19:15:21 +00:00
src cmd/compile: on AMD64, turn x < 128 into x <= 127 2025-02-16 07:23:13 -08:00
test cmd/compile: on AMD64, turn x < 128 into x <= 127 2025-02-16 07:23:13 -08:00
.gitattributes
.gitignore runtime,internal: move runtime/internal/sys to internal/runtime/sys 2024-07-23 19:05:35 +00:00
CONTRIBUTING.md doc: normalize proposal-process links 2023-03-29 22:00:27 +00:00
LICENSE LICENSE: update per Google Legal 2024-08-09 14:54:31 +00:00
PATENTS
README.md README: fix CC BY license name 2024-07-22 17:45:27 +00:00
SECURITY.md SECURITY.md: update the Reporting a Vulnerability link 2023-09-22 21:17:24 +00:00
codereview.cfg
go.env cmd/go: additional doc-inspired tests and bug fixes 2023-06-06 19:18:46 +00:00

README.md

The Go Programming Language

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Gopher image Gopher image by Renee French, licensed under Creative Commons 4.0 Attribution license.

Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.

Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.

Download and Install

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Contributing

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To contribute, please read the contribution guidelines at https://go.dev/doc/contribute.

Note that the Go project uses the issue tracker for bug reports and proposals only. See https://go.dev/wiki/Questions for a list of places to ask questions about the Go language.