Commit graph

3 commits

Author SHA1 Message Date
Keith Randall
dd24b1098a cmd/compile: improve tighten pass
Move a value to the block which is the lowest common ancestor in the
dominator tree of all of its uses.  Make sure not to move a value into a
loop.

Makes the tighten pass on average (across go1 benchmarks) 40% slower.
Still not a big contributor to overall compile time.

Binary size is just a tad smaller.

name                      old time/op    new time/op    delta
BinaryTree17-12              2.77s ± 9%     2.76s ± 9%     ~     (p=0.878 n=8+8)
Fannkuch11-12                2.75s ± 1%     2.74s ± 1%     ~     (p=0.232 n=8+7)
FmtFprintfEmpty-12          48.9ns ± 9%    47.7ns ± 0%     ~     (p=0.431 n=8+8)
FmtFprintfString-12          143ns ± 8%     142ns ± 1%     ~     (p=0.257 n=8+7)
FmtFprintfInt-12             123ns ± 1%     122ns ± 1%   -1.04%  (p=0.026 n=7+8)
FmtFprintfIntInt-12          195ns ± 7%     185ns ± 0%   -5.32%  (p=0.000 n=8+8)
FmtFprintfPrefixedInt-12     194ns ± 4%     195ns ± 0%   +0.81%  (p=0.015 n=7+7)
FmtFprintfFloat-12           267ns ± 0%     268ns ± 0%   +0.37%  (p=0.001 n=7+6)
FmtManyArgs-12               800ns ± 0%     762ns ± 1%   -4.78%  (p=0.000 n=8+8)
GobDecode-12                7.67ms ± 2%    7.60ms ± 2%     ~     (p=0.234 n=8+8)
GobEncode-12                6.55ms ± 0%    6.57ms ± 1%     ~     (p=0.336 n=7+8)
Gzip-12                      237ms ± 0%     238ms ± 0%   +0.40%  (p=0.017 n=7+7)
Gunzip-12                   40.8ms ± 0%    40.2ms ± 0%   -1.52%  (p=0.000 n=7+8)
HTTPClientServer-12          208µs ± 3%     209µs ± 3%     ~     (p=0.955 n=8+7)
JSONEncode-12               16.2ms ± 1%    17.2ms ±11%   +5.80%  (p=0.001 n=7+8)
JSONDecode-12               57.3ms ±12%    55.5ms ± 3%     ~     (p=0.867 n=8+7)
Mandelbrot200-12            4.68ms ± 6%    4.46ms ± 1%     ~     (p=0.442 n=8+8)
GoParse-12                  4.27ms ±44%    3.42ms ± 1%  -19.95%  (p=0.005 n=8+8)
RegexpMatchEasy0_32-12      75.1ns ± 0%    75.8ns ± 1%   +0.99%  (p=0.002 n=7+7)
RegexpMatchEasy0_1K-12       963ns ± 0%    1021ns ± 6%   +5.98%  (p=0.001 n=7+7)
RegexpMatchEasy1_32-12      72.4ns ±11%    70.8ns ± 1%     ~     (p=0.368 n=8+8)
RegexpMatchEasy1_1K-12       394ns ± 1%     399ns ± 0%   +1.23%  (p=0.000 n=8+7)
RegexpMatchMedium_32-12      114ns ± 0%     115ns ± 1%   +0.63%  (p=0.021 n=7+7)
RegexpMatchMedium_1K-12     35.9µs ± 0%    37.6µs ± 1%   +4.72%  (p=0.000 n=7+8)
RegexpMatchHard_32-12       1.93µs ± 2%    1.91µs ± 0%   -0.91%  (p=0.001 n=7+7)
RegexpMatchHard_1K-12       60.2µs ± 3%    61.2µs ±10%     ~     (p=0.442 n=8+8)
Revcomp-12                   404ms ± 1%     406ms ± 1%     ~     (p=0.054 n=8+7)
Template-12                 64.6ms ± 1%    63.5ms ± 1%   -1.66%  (p=0.000 n=8+8)
TimeParse-12                 347ns ± 8%     309ns ± 0%  -11.13%  (p=0.000 n=8+7)
TimeFormat-12                343ns ± 4%     331ns ± 0%   -3.34%  (p=0.000 n=8+7)

Change-Id: Id6da1239ddd4d0cb074ff29cffb06302d1c6d08f
Reviewed-on: https://go-review.googlesource.com/28712
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-20 22:49:48 +00:00
Keith Randall
4fa050024f cmd/compile: enable constant-time CFG editing
Provide indexes along with block pointers for Preds
and Succs arrays.  This allows us to splice edges in
and out of those arrays in constant time.

Fixes worst-case O(n^2) behavior in deadcode and fuse.

benchmark                     old ns/op      new ns/op     delta
BenchmarkFuse1-8              2065           2057          -0.39%
BenchmarkFuse10-8             9408           9073          -3.56%
BenchmarkFuse100-8            105238         76277         -27.52%
BenchmarkFuse1000-8           3982562        1026750       -74.22%
BenchmarkFuse10000-8          301220329      12824005      -95.74%
BenchmarkDeadCode1-8          1588           1566          -1.39%
BenchmarkDeadCode10-8         4333           4250          -1.92%
BenchmarkDeadCode100-8        32031          32574         +1.70%
BenchmarkDeadCode1000-8       590407         468275        -20.69%
BenchmarkDeadCode10000-8      17822890       5000818       -71.94%
BenchmarkDeadCode100000-8     1388706640     78021127      -94.38%
BenchmarkDeadCode200000-8     5372518479     168598762     -96.86%

Change-Id: Iccabdbb9343fd1c921ba07bbf673330a1c36ee17
Reviewed-on: https://go-review.googlesource.com/22589
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-05 15:58:59 +00:00
Keith Randall
3c26c0db39 [dev.ssa] cmd/compile: short-circuit empty blocks
Empty blocks are introduced to remove critical edges.
After regalloc, we can remove any of the added blocks
that are still empty.

Change-Id: I0b40e95ac3a6cc1e632a479443479532b6c5ccd9
Reviewed-on: https://go-review.googlesource.com/18833
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-01-22 22:12:12 +00:00