Michael Munday 2c1b5130aa cmd/compile: add math/bits.{Add,Sub}64 intrinsics on s390x
This CL adds intrinsics for the 64-bit addition and subtraction
functions in math/bits. These intrinsics use the condition code
to propagate the carry or borrow bit.

To make the carry chains more efficient I've removed the
'clobberFlags' property from most of the load and store
operations. Originally these ops did clobber flags when using
offsets that didn't fit in a signed 20-bit integer, however
that is no longer true.

As with other platforms the intrinsics are faster when executed
in a chain rather than a loop because currently we need to spill
and restore the carry bit between each loop iteration. We may
be able to reduce the need to do this on s390x (e.g. by using
compare-and-branch instructions that do not clobber flags) in the
future.

name           old time/op  new time/op  delta
Add64          1.21ns ± 2%  2.03ns ± 2%  +67.18%  (p=0.000 n=7+10)
Add64multiple  2.98ns ± 3%  1.03ns ± 0%  -65.39%  (p=0.000 n=10+9)
Sub64          1.23ns ± 4%  2.03ns ± 1%  +64.85%  (p=0.000 n=10+10)
Sub64multiple  3.73ns ± 4%  1.04ns ± 1%  -72.28%  (p=0.000 n=10+8)

Change-Id: I913bbd5e19e6b95bef52f5bc4f14d6fe40119083
Reviewed-on: https://go-review.googlesource.com/c/go/+/174303
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-05-03 10:41:15 +00:00
..
2019-03-06 18:53:12 +00:00
2018-05-29 02:39:16 +00:00
2015-01-29 13:07:30 +00:00
2018-10-06 15:40:03 +00:00
2015-07-11 14:36:33 +00:00
2015-07-11 14:36:33 +00:00
2017-08-11 17:41:17 +00:00
2018-04-30 19:39:18 +00:00
2019-03-18 20:10:55 +00:00
2014-10-27 18:59:02 -04:00
2018-11-26 14:13:53 +00:00
2018-11-27 15:36:08 +00:00
2018-11-26 14:13:53 +00:00
2018-11-26 14:13:53 +00:00
2019-03-12 20:46:29 +00:00
2018-03-01 21:11:16 +00:00
2018-12-03 16:48:21 +00:00

The test directory contains tests of the Go tool chain and runtime. It includes black box tests, regression tests, and error output tests. They are run as part of all.bash.

To run just these tests, execute:

../bin/go run run.go

Standard library tests should be written as regular Go tests in the appropriate package.

The tool chain and runtime also have regular Go tests in their packages. The main reasons to add a new test to this directory are:

  • it is most naturally expressed using the test runner; or
  • it is also applicable to gccgo and other Go tool chains.