• philhofer's avatar
    cmd/compile/internal/ssa: emit csel on arm64 · 2d0172c3
    philhofer authored
    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: 's avatarCherry Zhang <cherryyz@google.com>
    Reviewed-by: 's avatarKeith Randall <khr@golang.org>
    2d0172c3
rewrite.go 19.6 KB