tree 467e7c6a8b9a6a1f02fbfa556882c94235686a1c
parent 9fba50545d4d992798b73eaf3c4a923b1f7ec20e
author philhofer <phofer@umich.edu> 1502663807 +0000
committer Brad Fitzpatrick <bradfitz@golang.org> 1519106454 +0000

cmd/compile/internal/ssa: emit csel on arm64

Introduce a new SSA pass to generate CondSelect intstrutions,
and add CondSelect lowering rules for arm64.

In order to make the CSEL instruction easier to optimize,
and to simplify the introduction of CSNEG, CSINC, and CSINV
in the future, modify the CSEL instruction to accept a condition
code in the aux field.

Notably, this change makes the go1 Gzip benchmark
more than 10% faster.

Benchmarks on a Cavium ThunderX:

name                      old time/op    new time/op    delta
BinaryTree17-96              15.9s ± 6%     16.0s ± 4%     ~     (p=0.968 n=10+9)
Fannkuch11-96                7.17s ± 0%     7.00s ± 0%   -2.43%  (p=0.000 n=8+9)
FmtFprintfEmpty-96           208ns ± 1%     207ns ± 0%     ~     (p=0.152 n=10+8)
FmtFprintfString-96          379ns ± 0%     375ns ± 0%   -0.95%  (p=0.000 n=10+9)
FmtFprintfInt-96             385ns ± 0%     383ns ± 0%   -0.52%  (p=0.000 n=9+10)
FmtFprintfIntInt-96          591ns ± 0%     586ns ± 0%   -0.85%  (p=0.006 n=7+9)
FmtFprintfPrefixedInt-96     656ns ± 0%     667ns ± 0%   +1.71%  (p=0.000 n=10+10)
FmtFprintfFloat-96           967ns ± 0%     984ns ± 0%   +1.78%  (p=0.000 n=10+10)
FmtManyArgs-96              2.35µs ± 0%    2.25µs ± 0%   -4.63%  (p=0.000 n=9+8)
GobDecode-96                31.0ms ± 0%    30.8ms ± 0%   -0.36%  (p=0.006 n=9+9)
GobEncode-96                24.4ms ± 0%    24.5ms ± 0%   +0.30%  (p=0.000 n=9+9)
Gzip-96                      1.60s ± 0%     1.43s ± 0%  -10.58%  (p=0.000 n=9+10)
Gunzip-96                    167ms ± 0%     169ms ± 0%   +0.83%  (p=0.000 n=8+9)
HTTPClientServer-96          311µs ± 1%     308µs ± 0%   -0.75%  (p=0.000 n=10+10)
JSONEncode-96               65.0ms ± 0%    64.8ms ± 0%   -0.25%  (p=0.000 n=9+8)
JSONDecode-96                262ms ± 1%     261ms ± 1%     ~     (p=0.579 n=10+10)
Mandelbrot200-96            18.0ms ± 0%    18.1ms ± 0%   +0.17%  (p=0.000 n=8+10)
GoParse-96                  14.0ms ± 0%    14.1ms ± 1%   +0.42%  (p=0.003 n=9+10)
RegexpMatchEasy0_32-96       644ns ± 2%     645ns ± 2%     ~     (p=0.836 n=10+10)
RegexpMatchEasy0_1K-96      3.70µs ± 0%    3.49µs ± 0%   -5.58%  (p=0.000 n=10+10)
RegexpMatchEasy1_32-96       662ns ± 2%     657ns ± 2%     ~     (p=0.137 n=10+10)
RegexpMatchEasy1_1K-96      4.47µs ± 0%    4.31µs ± 0%   -3.48%  (p=0.000 n=10+10)
RegexpMatchMedium_32-96      844ns ± 2%     849ns ± 1%     ~     (p=0.208 n=10+10)
RegexpMatchMedium_1K-96      179µs ± 0%     182µs ± 0%   +1.20%  (p=0.000 n=10+10)
RegexpMatchHard_32-96       10.0µs ± 0%    10.1µs ± 0%   +0.48%  (p=0.000 n=10+9)
RegexpMatchHard_1K-96        297µs ± 0%     297µs ± 0%   -0.14%  (p=0.000 n=10+10)
Revcomp-96                   3.08s ± 0%     3.13s ± 0%   +1.56%  (p=0.000 n=9+9)
Template-96                  276ms ± 2%     275ms ± 1%     ~     (p=0.393 n=10+10)
TimeParse-96                1.37µs ± 0%    1.36µs ± 0%   -0.53%  (p=0.000 n=10+7)
TimeFormat-96               1.40µs ± 0%    1.42µs ± 0%   +0.97%  (p=0.000 n=10+10)
[Geo mean]                   264µs          262µs        -0.77%

Change-Id: Ie54eee4b3092af53e6da3baa6d1755098f57f3a2
Reviewed-on: https://go-review.googlesource.com/55670
Run-TryBot: Philip Hofer <phofer@umich.edu>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>