a3f234c706
CL 213703 converted generated rewrite rules for commutative ops to use loops instead of duplicated code. However, it loaded args using expressions like v.Args[i] and v.Args[i^1], which the compiler could not eliminate bounds for (including with all outstanding prove CLs). Also, given a series of separate rewrite rules for the same op, we generated bounds checks for every rewrite rule, even though we were repeatedly loading the same set of args. This change reduces both sets of bounds checks. Instead of loading v.Args[i] and v.Args[i^1] for commutative loops, we now preload v.Args[0] and v.Args[1] into local variables, and then swap them (as needed) in the commutative loop post statement. And we now load all top level v.Args into local variables at the beginning of every rewrite rule function. The second optimization is the more significant, but the first helps a little, and they play together nicely from the perspective of generating the code. This does increase register pressure, but the reduced bounds checks more than compensate. Note that the vast majority of rewrite rules evaluated are not applied, so the prologue is the most important part of the rewrite rules. There is one subtle aspect to the new generated code. Because the top level v.Args are shared across rewrite rules, and rule evaluation can swap v_0 and v_1, v_0 and v_1 can end up being swapped from one rule to the next. That is OK, because any time a rule does not get applied, they will have been swapped exactly twice. Passes toolstash-check -all. name old time/op new time/op delta Template 213ms ± 2% 211ms ± 2% -0.85% (p=0.000 n=92+96) Unicode 83.5ms ± 2% 83.2ms ± 2% -0.41% (p=0.004 n=95+90) GoTypes 737ms ± 2% 733ms ± 2% -0.51% (p=0.000 n=91+94) Compiler 3.45s ± 2% 3.43s ± 2% -0.44% (p=0.000 n=99+100) SSA 8.54s ± 1% 8.32s ± 2% -2.56% (p=0.000 n=96+99) Flate 136ms ± 2% 135ms ± 1% -0.47% (p=0.000 n=96+96) GoParser 169ms ± 1% 168ms ± 1% -0.33% (p=0.000 n=96+93) Reflect 456ms ± 3% 455ms ± 3% ~ (p=0.261 n=95+94) Tar 186ms ± 2% 185ms ± 2% -0.48% (p=0.000 n=94+95) XML 251ms ± 1% 250ms ± 1% -0.51% (p=0.000 n=91+94) [Geo mean] 424ms 421ms -0.68% name old user-time/op new user-time/op delta Template 275ms ± 1% 274ms ± 2% -0.55% (p=0.000 n=95+98) Unicode 118ms ± 4% 118ms ± 4% ~ (p=0.642 n=98+90) GoTypes 983ms ± 1% 980ms ± 1% -0.30% (p=0.000 n=93+93) Compiler 4.56s ± 6% 4.52s ± 6% -0.72% (p=0.003 n=100+100) SSA 11.4s ± 1% 11.1s ± 1% -2.50% (p=0.000 n=96+97) Flate 168ms ± 1% 167ms ± 1% -0.49% (p=0.000 n=92+92) GoParser 204ms ± 1% 204ms ± 2% -0.27% (p=0.003 n=99+96) Reflect 599ms ± 2% 598ms ± 2% ~ (p=0.116 n=95+92) Tar 227ms ± 2% 225ms ± 2% -0.57% (p=0.000 n=95+98) XML 313ms ± 2% 312ms ± 1% -0.37% (p=0.000 n=89+95) [Geo mean] 547ms 544ms -0.61% file before after Δ % compile 21113112 21109016 -4096 -0.019% total 131704940 131700844 -4096 -0.003% Change-Id: Id6c39e0367e597c0c75b8a4b1eb14cc3cbd11956 Reviewed-on: https://go-review.googlesource.com/c/go/+/216218 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> |
||
|---|---|---|
| .github | ||
| api | ||
| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| favicon.ico | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| robots.txt | ||
| SECURITY.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 by Renee French, licensed under Creative Commons 3.0 Attributions 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
Binary Distributions
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
Install From Source
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Contributing
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.