Lynn Boger a1550d3ca3 cmd/compile: use isel with variable shifts on ppc64x
This changes the code generated for variable length shift
counts to use isel instead of instructions that set and
read the carry flag.

This reduces the generated code for shifts like this
by 1 instruction and avoids the use of instructions to
set and read the carry flag.

This sequence can be found in strconv with these results
on power9:

Atof64Decimal                          71.6ns ± 0%  68.3ns ± 0%   -4.61%
Atof64Float                            95.3ns ± 0%  90.9ns ± 0%   -4.62%
Atof64FloatExp                          153ns ± 0%   149ns ± 0%   -2.61%
Atof64Big                               234ns ± 0%   232ns ± 0%   -0.85%
Atof64RandomBits                        348ns ± 0%   369ns ± 0%   +6.03%
Atof64RandomFloats                      262ns ± 0%   262ns ± 0%     ~
Atof32Decimal                          72.0ns ± 0%  68.2ns ± 0%   -5.28%
Atof32Float                            92.1ns ± 0%  87.1ns ± 0%   -5.43%
Atof32FloatExp                          159ns ± 0%   158ns ± 0%   -0.63%
Atof32Random                            194ns ± 0%   191ns ± 0%   -1.55%

Some tests in codegen/shift.go are enabled to verify the
expected instructions are generated.

Change-Id: I968715d10ada405a8c46132bf19b8ed9b85796d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/227337
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-04-09 19:18:56 +00:00
..
2019-03-06 18:53:12 +00:00
2020-03-25 22:22:20 +00:00
2019-09-08 17:28:20 +00:00
2018-05-29 02:39:16 +00:00
2015-01-29 13:07:30 +00:00
2019-09-08 17:28:20 +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
2019-09-25 17:06:15 +00:00
2019-09-25 17:06:15 +00:00
2019-09-08 17:28:20 +00:00
2018-04-30 19:39:18 +00:00
2019-09-08 17:28:20 +00:00
2019-03-18 20:10:55 +00:00
2019-11-01 20:13:05 +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
2019-09-08 17:28:20 +00:00
2018-03-01 21:11:16 +00:00
2018-12-03 16:48:21 +00:00
2019-09-08 17:28:20 +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.