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3 Commits

Author SHA1 Message Date
Michael Munday
854e892ce1 cmd/compile: optimize shift pairs and masks on s390x 
Optimize combinations of left and right shifts by a constant value
into a 'rotate then insert selected bits [into zero]' instruction.
Use the same instruction for contiguous masks since it has some
benefits over 'and immediate' (not restricted to 32-bits, does not
overwrite source register).

To keep the complexity of this change under control I've only
implemented 64 bit operations for now.

There are a lot more optimizations that can be done with this
instruction family. However, since their function overlaps with other
instructions we need to be somewhat careful not to break existing
optimization rules by creating optimization dead ends. This is
particularly true of the load/store merging rules which contain lots
of zero extensions and shifts.

This CL does interfere with the store merging rules when an operand
is shifted left before it is stored:

  binary.BigEndian.PutUint64(b, x << 1)

This is unfortunate but it's not critical and somewhat complex so
I plan to fix that in a follow up CL.

file      before    after     Δ       %
addr2line 4117446   4117282   -164    -0.004%
api       4945184   4942752   -2432   -0.049%
asm       4998079   4991891   -6188   -0.124%
buildid   2685158   2684074   -1084   -0.040%
cgo       4553732   4553394   -338    -0.007%
compile   19294446  19245070  -49376  -0.256%
cover     4897105   4891319   -5786   -0.118%
dist      3544389   3542785   -1604   -0.045%
doc       3926795   3927617   +822    +0.021%
fix       3302958   3293868   -9090   -0.275%
link      6546274   6543456   -2818   -0.043%
nm        4102021   4100825   -1196   -0.029%
objdump   4542431   4548483   +6052   +0.133%
pack      2482465   2416389   -66076  -2.662%
pprof     13366541  13363915  -2626   -0.020%
test2json 2829007   2761515   -67492  -2.386%
trace     10216164  10219684  +3520   +0.034%
vet       6773956   6773572   -384    -0.006%
total     107124151 106917891 -206260 -0.193%

Change-Id: I7591cce41e06867ba10a745daae9333513062746
Reviewed-on: https://go-review.googlesource.com/c/go/+/233317
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Michael Munday <mike.munday@ibm.com>
 2020-11-06 10:45:31 +00:00
Alberto Donizetti
d5ff631e6b test/codegen: port last remaining misc bit/arithmetic tests 
And delete them from asm_test.

Change-Id: I9a75efe9858ef9d7ac86065f860c2ae3f25b0941
Reviewed-on: https://go-review.googlesource.com/105597
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
 2018-04-10 07:58:35 +00:00
Geoff Berry
e244a7a7d3 cmd/compile/internal/ssa: add patterns for arm64 bitfield opcodes 
Add patterns to match common idioms for EXTR, BFI, BFXIL, SBFIZ, SBFX,
UBFIZ and UBFX opcodes.

go1 benchmarks results on Amberwing:
name                   old time/op    new time/op    delta
FmtManyArgs               786ns ± 2%     714ns ± 1%  -9.20%  (p=0.000 n=10+10)
Gzip                      437ms ± 0%     402ms ± 0%  -7.99%  (p=0.000 n=10+10)
FmtFprintfIntInt          196ns ± 0%     182ns ± 0%  -7.28%  (p=0.000 n=10+9)
FmtFprintfPrefixedInt     207ns ± 0%     199ns ± 0%  -3.86%  (p=0.000 n=10+10)
FmtFprintfFloat           324ns ± 0%     316ns ± 0%  -2.47%  (p=0.000 n=10+8)
FmtFprintfInt             119ns ± 0%     117ns ± 0%  -1.68%  (p=0.000 n=10+9)
GobDecode                12.8ms ± 2%    12.6ms ± 1%  -1.62%  (p=0.002 n=10+10)
JSONDecode               94.4ms ± 1%    93.4ms ± 0%  -1.10%  (p=0.000 n=10+10)
RegexpMatchEasy0_32       247ns ± 0%     245ns ± 0%  -0.65%  (p=0.000 n=10+10)
RegexpMatchMedium_32      314ns ± 0%     312ns ± 0%  -0.64%  (p=0.000 n=10+10)
RegexpMatchEasy0_1K       541ns ± 0%     538ns ± 0%  -0.55%  (p=0.000 n=10+9)
TimeParse                 450ns ± 1%     448ns ± 1%  -0.42%  (p=0.035 n=9+9)
RegexpMatchEasy1_32       244ns ± 0%     243ns ± 0%  -0.41%  (p=0.000 n=10+10)
GoParse                  6.03ms ± 0%    6.00ms ± 0%  -0.40%  (p=0.002 n=10+10)
RegexpMatchEasy1_1K       779ns ± 0%     777ns ± 0%  -0.26%  (p=0.000 n=10+10)
RegexpMatchHard_32       2.75µs ± 0%    2.74µs ± 1%  -0.06%  (p=0.026 n=9+9)
BinaryTree17              11.7s ± 0%     11.6s ± 0%    ~     (p=0.089 n=10+10)
HTTPClientServer         89.1µs ± 1%    89.5µs ± 2%    ~     (p=0.436 n=10+10)
RegexpMatchHard_1K       78.9µs ± 0%    79.5µs ± 2%    ~     (p=0.469 n=10+10)
FmtFprintfEmpty          58.5ns ± 0%    58.5ns ± 0%    ~     (all equal)
GobEncode                12.0ms ± 1%    12.1ms ± 0%    ~     (p=0.075 n=10+10)
Revcomp                   669ms ± 0%     668ms ± 0%    ~     (p=0.091 n=7+9)
Mandelbrot200            5.35ms ± 0%    5.36ms ± 0%  +0.07%  (p=0.000 n=9+9)
RegexpMatchMedium_1K     52.1µs ± 0%    52.1µs ± 0%  +0.10%  (p=0.000 n=9+9)
Fannkuch11                3.25s ± 0%     3.26s ± 0%  +0.36%  (p=0.000 n=9+10)
FmtFprintfString          114ns ± 1%     115ns ± 0%  +0.52%  (p=0.011 n=10+10)
JSONEncode               20.2ms ± 0%    20.3ms ± 0%  +0.65%  (p=0.000 n=10+10)
Template                 91.3ms ± 0%    92.3ms ± 0%  +1.08%  (p=0.000 n=10+10)
TimeFormat                484ns ± 0%     495ns ± 1%  +2.30%  (p=0.000 n=9+10)

There are some opportunities to improve this change further by adding
patterns to match the "extended register" versions of ADD/SUB/CMP, but I
think that should be evaluated on its own.  The regressions in Template
and TimeFormat would likely be recovered by this, as they seem to be due
to generating:

    ubfiz x0, x0, #3, #8
    add x1, x2, x0

instead of

    add x1, x2, x0, lsl #3

Change-Id: I5644a8d70ac7a98e784a377a2b76ab47a3415a4b
Reviewed-on: https://go-review.googlesource.com/88355
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
 2018-03-15 14:10:41 +00:00