cmd/compile, runtime: intrinsify atomic And8 and Or8 on s390x

Intrinsify these functions to match other platforms. Update the
sequence of instructions used in the assembly implementations to
match the intrinsics.

Also, add a micro benchmark so we can more easily measure the
performance of these two functions:

name            old time/op  new time/op  delta
And8-8          5.33ns ± 7%  2.55ns ± 8%  -52.12%  (p=0.000 n=20+20)
And8Parallel-8  7.39ns ± 5%  3.74ns ± 4%  -49.34%  (p=0.000 n=20+20)
Or8-8           4.84ns ±15%  2.64ns ±11%  -45.50%  (p=0.000 n=20+20)
Or8Parallel-8   7.27ns ± 3%  3.84ns ± 4%  -47.10%  (p=0.000 n=19+20)

By using a 'rotate then xor selected bits' instruction combined with
either a 'load and and' or a 'load and or' instruction we can
implement And8 and Or8 with far fewer instructions. Replacing
'compare and swap' with atomic instructions may also improve
performance when there is contention.

Change-Id: I28bb8032052b73ae8ccdf6e4c612d2877085fa01
Reviewed-on: https://go-review.googlesource.com/c/go/+/204277
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
9 files changed
tree: c7f9c66dbe89b891b512347b0e56cf69d253a387
  1. .github/
  2. api/
  3. doc/
  4. lib/
  5. misc/
  6. src/
  7. test/
  8. .gitattributes
  9. .gitignore
  10. AUTHORS
  11. CONTRIBUTING.md
  12. CONTRIBUTORS
  13. favicon.ico
  14. LICENSE
  15. PATENTS
  16. README.md
  17. robots.txt
  18. SECURITY.md
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 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.