Commit graph

7 commits

Author SHA1 Message Date
Martin Möhrmann
a8a60ac2a7 cmd/compile: optimize append(x, make([]T, y)...) slice extension
Changes the compiler to recognize the slice extension pattern

  append(x, make([]T, y)...)

and replace it with growslice and an optional memclr to avoid an allocation for make([]T, y).

Memclr is not called in case growslice already allocated a new cleared backing array
when T contains pointers.

amd64:
name                      old time/op    new time/op    delta
ExtendSlice/IntSlice         103ns ± 4%      57ns ± 4%   -44.55%  (p=0.000 n=18+18)
ExtendSlice/PointerSlice     155ns ± 3%      77ns ± 3%   -49.93%  (p=0.000 n=20+20)
ExtendSlice/NoGrow          50.2ns ± 3%     5.2ns ± 2%   -89.67%  (p=0.000 n=18+18)

name                      old alloc/op   new alloc/op   delta
ExtendSlice/IntSlice         64.0B ± 0%     32.0B ± 0%   -50.00%  (p=0.000 n=20+20)
ExtendSlice/PointerSlice     64.0B ± 0%     32.0B ± 0%   -50.00%  (p=0.000 n=20+20)
ExtendSlice/NoGrow           32.0B ± 0%      0.0B       -100.00%  (p=0.000 n=20+20)

name                      old allocs/op  new allocs/op  delta
ExtendSlice/IntSlice          2.00 ± 0%      1.00 ± 0%   -50.00%  (p=0.000 n=20+20)
ExtendSlice/PointerSlice      2.00 ± 0%      1.00 ± 0%   -50.00%  (p=0.000 n=20+20)
ExtendSlice/NoGrow            1.00 ± 0%      0.00       -100.00%  (p=0.000 n=20+20)

Fixes #21266

Change-Id: Idc3077665f63cbe89762b590c5967a864fd1c07f
Reviewed-on: https://go-review.googlesource.com/109517
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-05-06 04:28:23 +00:00
Rob Pike
fc0dc04095 test: [a-c]: add introductory comments to tests
Very few of the compiler regression tests include a comment
saying waht they do. Many are obvious, some are anything but.
I've started with a-c in the top directory. More will follow once
we agree on the approach, correctness, and thoroughness here.
zerodivide.go sneaked in too.

R=rsc, r
CC=golang-dev
https://golang.org/cl/5656100
2012-02-19 13:19:43 +11:00
Russ Cox
0b477ef17e test: use testlib (first 100)
X ,s;^// \$G (\$D/)?\$F\.go *$;// compile;g
X ,s;^// \$G (\$D/)?\$F\.go && \$L \$F\.\$A *$;// build;g
X ,s;^// \$G (\$D/)?\$F\.go && \$L \$F\.\$A && \./\$A\.out *$;// run;g
X ,s;^// errchk \$G( -e)? (\$D/)?\$F\.go *$;// errorcheck;g

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5656082
2012-02-16 23:48:57 -05:00
Ian Lance Taylor
3692726f32 test: test append with two different named types with same element type
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5615045
2012-02-01 15:24:15 -08:00
Luuk van Dijk
77fac21e82 runtime: append([]byte, string...)
Fixes #2274

R=rsc, gri, dsymonds, bradfitz, lvd
CC=golang-dev
https://golang.org/cl/5149045
2011-10-12 15:59:23 +02:00
Russ Cox
f2b5a07453 delete float, complex - code changes
also:
	cmplx -> complex
	float64(1.0) -> 1.0
	float64(1) -> 1.0

R=gri, r, gri1, r2
CC=golang-dev
https://golang.org/cl/3991043
2011-01-19 23:09:00 -05:00
Robert Griesemer
e79ebb008f test for append() built-in
R=r, rsc
CC=golang-dev
https://golang.org/cl/2777041
2010-10-28 08:14:31 -07:00