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Commit Graph

5 Commits

Author SHA1 Message Date
Keith Randall
aaa3d39f27 cmd/compile: include all entries in map literal hint size
Currently we only include static entries in the hint for sizing
the map when allocating a map for a map literal. Change that to
include all entries.

This will be an overallocation if the dynamic entries in the map have
equal keys, but equal keys in map literals are rare, and at worst we
waste a bit of space.

Fixes #43020

Change-Id: I232f82f15316bdf4ea6d657d25a0b094b77884ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/383634
Run-TryBot: Keith Randall <khr@golang.org>
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-03-01 23:20:30 +00:00
Cherry Zhang
263e13d1f7 test: make codegen tests work with both ABIs
Some codegen tests were written with the assumption that
arguments and results are in memory, and with a specific stack
layout. With the register ABI, the assumption is no longer true.
Adjust the tests to work with both cases.

- For tests expecting in memory arguments/results, change to use
  global variables or memory-assigned argument/results.

- Allow more registers. E.g. some tests expecting register names
  contain only letters (e.g. AX), but  it can also contain numbers
  (e.g. R10).

- Some instruction selection changes when operate on register vs.
  memory, e.g. ADDQ vs. LEAQ, MOVB vs. MOVL. Accept both.

TODO: mathbits.go and memops.go still need fix.
Change-Id: Ic5932b4b5dd3f5d30ed078d296476b641420c4c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/309335
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2021-04-12 21:59:59 +00:00
Martin Möhrmann
a0f57c3fd0 cmd/compile: avoid string allocations when map key is struct or array literal
x = map[string(byteslice)] is already optimized by the compiler to avoid a
string allocation. This CL generalizes this optimization to:

x = map[T1{ ... Tn{..., string(byteslice), ...} ... }]
where T1 to Tn is a nesting of struct and array literals.

Found in a hot code path that used a struct of strings made from []byte
slices to make a map lookup.

There are no uses of the more generalized optimization in the standard library.
Passes toolstash -cmp.

MapStringConversion/32/simple    21.9ns ± 2%    21.9ns ± 3%      ~     (p=0.995 n=17+20)
MapStringConversion/32/struct    28.8ns ± 3%    22.0ns ± 2%   -23.80%  (p=0.000 n=20+20)
MapStringConversion/32/array     28.5ns ± 2%    21.9ns ± 2%   -23.14%  (p=0.000 n=19+16)
MapStringConversion/64/simple    21.0ns ± 2%    21.1ns ± 3%      ~     (p=0.072 n=19+18)
MapStringConversion/64/struct    72.4ns ± 3%    21.3ns ± 2%   -70.53%  (p=0.000 n=20+20)
MapStringConversion/64/array     72.8ns ± 1%    21.0ns ± 2%   -71.13%  (p=0.000 n=17+19)

name                           old allocs/op  new allocs/op  delta
MapStringConversion/32/simple      0.00           0.00           ~     (all equal)
MapStringConversion/32/struct      0.00           0.00           ~     (all equal)
MapStringConversion/32/array       0.00           0.00           ~     (all equal)
MapStringConversion/64/simple      0.00           0.00           ~     (all equal)
MapStringConversion/64/struct      1.00 ± 0%      0.00       -100.00%  (p=0.000 n=20+20)
MapStringConversion/64/array       1.00 ± 0%      0.00       -100.00%  (p=0.000 n=20+20)

Change-Id: I483b4d84d8d74b1025b62c954da9a365e79b7a3a
Reviewed-on: https://go-review.googlesource.com/c/116275
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-10-15 19:22:07 +00:00
Martin Möhrmann
aee71dd70b cmd/compile: optimize map-clearing range idiom
replace map clears of the form:

        for k := range m {
                delete(m, k)
        }

(where m is map with key type that is reflexive for ==)
with a new runtime function that clears the maps backing
array with a memclr and reinitializes the hmap struct.

Map key types that for example contain floats are not
replaced by this optimization since NaN keys cannot
be deleted from maps using delete.

name                           old time/op  new time/op  delta
GoMapClear/Reflexive/1         92.2ns ± 1%  47.1ns ± 2%  -48.89%  (p=0.000 n=9+9)
GoMapClear/Reflexive/10         108ns ± 1%    48ns ± 2%  -55.68%  (p=0.000 n=10+10)
GoMapClear/Reflexive/100        303ns ± 2%   110ns ± 3%  -63.56%  (p=0.000 n=10+10)
GoMapClear/Reflexive/1000      3.58µs ± 3%  1.23µs ± 2%  -65.49%  (p=0.000 n=9+10)
GoMapClear/Reflexive/10000     28.2µs ± 3%  10.3µs ± 2%  -63.55%  (p=0.000 n=9+10)
GoMapClear/NonReflexive/1       121ns ± 2%   124ns ± 7%     ~     (p=0.097 n=10+10)
GoMapClear/NonReflexive/10      137ns ± 2%   139ns ± 3%   +1.53%  (p=0.033 n=10+10)
GoMapClear/NonReflexive/100     331ns ± 3%   334ns ± 2%     ~     (p=0.342 n=10+10)
GoMapClear/NonReflexive/1000   3.64µs ± 3%  3.64µs ± 2%     ~     (p=0.887 n=9+10)
GoMapClear/NonReflexive/10000  28.1µs ± 2%  28.4µs ± 3%     ~     (p=0.247 n=10+10)

Fixes #20138

Change-Id: I181332a8ef434a4f0d89659f492d8711db3f3213
Reviewed-on: https://go-review.googlesource.com/110055
Reviewed-by: Keith Randall <khr@golang.org>
2018-05-08 21:15:16 +00:00
Alberto Donizetti
5a4e09837c test/codegen: port maps test to codegen
And delete them from asm_test.

Change-Id: I3cf0934706a640136cb0f646509174f8c1bf3363
Reviewed-on: https://go-review.googlesource.com/101395
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
2018-03-19 13:39:34 +00:00