f876fb9bae
When allocating registers, before kicking out the existing value, copy it to a spare register if there is one. So later use of this value can be found in register instead of reload from spill. This is very helpful for instructions of which the input and/or output can only be in specific registers, e.g. DIV on x86, MUL/DIV on MIPS. May also be helpful in general. For "go build -a cmd/go" on AMD64, reduce "spilled value remains" by 1% (not including args, which almost certainly remain). For the code in issue #16061 on AMD64: MaxRem-12 111µs ± 1% 94µs ± 0% -15.38% (p=0.008 n=5+5) Go1 benchmark on AMD64: BinaryTree17-12 2.32s ± 2% 2.30s ± 1% ~ (p=0.421 n=5+5) Fannkuch11-12 2.52s ± 0% 2.44s ± 0% -3.44% (p=0.008 n=5+5) FmtFprintfEmpty-12 39.9ns ± 3% 39.8ns ± 0% ~ (p=0.635 n=5+4) FmtFprintfString-12 114ns ± 1% 113ns ± 1% ~ (p=0.905 n=5+5) FmtFprintfInt-12 102ns ± 6% 98ns ± 1% ~ (p=0.087 n=5+5) FmtFprintfIntInt-12 146ns ± 5% 147ns ± 1% ~ (p=0.238 n=5+5) FmtFprintfPrefixedInt-12 155ns ± 2% 151ns ± 1% -2.58% (p=0.008 n=5+5) FmtFprintfFloat-12 231ns ± 1% 232ns ± 1% ~ (p=0.286 n=5+5) FmtManyArgs-12 657ns ± 1% 649ns ± 0% -1.31% (p=0.008 n=5+5) GobDecode-12 6.35ms ± 0% 6.29ms ± 1% ~ (p=0.056 n=5+5) GobEncode-12 5.38ms ± 1% 5.45ms ± 1% ~ (p=0.056 n=5+5) Gzip-12 209ms ± 0% 209ms ± 1% ~ (p=0.690 n=5+5) Gunzip-12 31.2ms ± 1% 31.1ms ± 1% ~ (p=0.548 n=5+5) HTTPClientServer-12 123µs ± 4% 130µs ± 8% ~ (p=0.151 n=5+5) JSONEncode-12 14.0ms ± 1% 14.0ms ± 1% ~ (p=0.421 n=5+5) JSONDecode-12 41.2ms ± 1% 41.1ms ± 2% ~ (p=0.421 n=5+5) Mandelbrot200-12 3.96ms ± 1% 3.98ms ± 0% ~ (p=0.421 n=5+5) GoParse-12 2.88ms ± 1% 2.88ms ± 1% ~ (p=0.841 n=5+5) RegexpMatchEasy0_32-12 68.0ns ± 3% 66.6ns ± 1% -2.00% (p=0.024 n=5+5) RegexpMatchEasy0_1K-12 728ns ± 8% 682ns ± 1% -6.26% (p=0.008 n=5+5) RegexpMatchEasy1_32-12 66.8ns ± 2% 66.0ns ± 1% ~ (p=0.302 n=5+5) RegexpMatchEasy1_1K-12 291ns ± 2% 288ns ± 1% ~ (p=0.111 n=5+5) RegexpMatchMedium_32-12 103ns ± 2% 100ns ± 0% -2.53% (p=0.016 n=5+4) RegexpMatchMedium_1K-12 31.9µs ± 1% 31.3µs ± 0% -1.75% (p=0.008 n=5+5) RegexpMatchHard_32-12 1.59µs ± 2% 1.59µs ± 1% ~ (p=0.548 n=5+5) RegexpMatchHard_1K-12 48.3µs ± 2% 47.7µs ± 1% ~ (p=0.222 n=5+5) Revcomp-12 340ms ± 1% 338ms ± 1% ~ (p=0.421 n=5+5) Template-12 46.3ms ± 1% 46.5ms ± 1% ~ (p=0.690 n=5+5) TimeParse-12 252ns ± 1% 247ns ± 0% -1.91% (p=0.000 n=5+4) TimeFormat-12 277ns ± 1% 267ns ± 0% -3.82% (p=0.008 n=5+5) [Geo mean] 48.8µs 48.3µs -0.93% It has very little effect on binary size and compiler speed. compilebench: Template 230ms ±10% 231ms ± 8% ~ (p=0.546 n=9+9) Unicode 123ms ± 6% 124ms ± 9% ~ (p=0.481 n=10+10) GoTypes 742ms ± 6% 755ms ± 3% ~ (p=0.123 n=10+10) Compiler 3.10s ± 3% 3.08s ± 1% ~ (p=0.631 n=10+10) Fixes #16061. Change-Id: Id99cdc7a182ee10a704fa0f04e8e0d0809b2ac56 Reviewed-on: https://go-review.googlesource.com/29732 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com> |
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The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
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.
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only. Please ask questions on https://forum.golangbridge.org or https://groups.google.com/forum/#!forum/golang-nuts.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.