Russ Cox d447279927 cmd/internal/gc: optimize slice + write barrier ... The code generated for a slice x[i:j] or x[i:j:k] computes the entire new slice (base, len, cap) and then uses it as the evaluation of the slice expression. If the slice is part of an update x = x[i:j] or x = x[i:j:k], there are opportunities to avoid computing some of these fields. For x = x[0:i], we know that only the len is changing; base can be ignored completely, and cap can be left unmodified. For x = x[0:i:j], we know that only len and cap are changing; base can be ignored completely. For x = x[i:i], we know that the resulting cap is zero, and we don't adjust the base during a slice producing a zero-cap result, so again base can be ignored completely. No write to base, no write barrier. The old slice code was trying to work at a Go syntax level, mainly because that was how you wrote code just once instead of once per architecture. Now the compiler is factored a bit better and we can implement slice during code generation but still have one copy of the code. So the new code is working at that lower level. (It must, to update only parts of the result.) This CL by itself: name old mean new mean delta BinaryTree17 5.81s × (0.98,1.03) 5.71s × (0.96,1.05) ~ (p=0.101) Fannkuch11 4.35s × (1.00,1.00) 4.39s × (1.00,1.00) +0.79% (p=0.000) FmtFprintfEmpty 86.0ns × (0.94,1.11) 82.6ns × (0.98,1.04) -3.86% (p=0.048) FmtFprintfString 276ns × (0.98,1.04) 273ns × (0.98,1.02) ~ (p=0.235) FmtFprintfInt 274ns × (0.98,1.06) 270ns × (0.99,1.01) ~ (p=0.119) FmtFprintfIntInt 506ns × (0.99,1.01) 475ns × (0.99,1.01) -6.02% (p=0.000) FmtFprintfPrefixedInt 391ns × (0.99,1.01) 393ns × (1.00,1.01) ~ (p=0.139) FmtFprintfFloat 566ns × (0.99,1.01) 574ns × (1.00,1.01) +1.33% (p=0.001) FmtManyArgs 1.91µs × (0.99,1.01) 1.87µs × (0.99,1.02) -1.83% (p=0.000) GobDecode 15.3ms × (0.99,1.02) 15.0ms × (0.98,1.05) -1.84% (p=0.042) GobEncode 11.5ms × (0.97,1.03) 11.4ms × (0.99,1.03) ~ (p=0.152) Gzip 645ms × (0.99,1.01) 647ms × (0.99,1.01) ~ (p=0.265) Gunzip 142ms × (1.00,1.00) 143ms × (1.00,1.01) +0.90% (p=0.000) HTTPClientServer 90.5µs × (0.97,1.04) 88.5µs × (0.99,1.03) -2.27% (p=0.014) JSONEncode 32.0ms × (0.98,1.03) 29.6ms × (0.98,1.01) -7.51% (p=0.000) JSONDecode 114ms × (0.99,1.01) 104ms × (1.00,1.01) -8.60% (p=0.000) Mandelbrot200 6.04ms × (1.00,1.01) 6.02ms × (1.00,1.00) ~ (p=0.057) GoParse 6.47ms × (0.97,1.05) 6.37ms × (0.97,1.04) ~ (p=0.105) RegexpMatchEasy0_32 171ns × (0.93,1.07) 152ns × (0.99,1.01) -11.09% (p=0.000) RegexpMatchEasy0_1K 550ns × (0.98,1.01) 530ns × (1.00,1.00) -3.78% (p=0.000) RegexpMatchEasy1_32 135ns × (0.99,1.02) 134ns × (0.99,1.01) -1.33% (p=0.002) RegexpMatchEasy1_1K 879ns × (1.00,1.01) 865ns × (1.00,1.00) -1.58% (p=0.000) RegexpMatchMedium_32 243ns × (1.00,1.00) 233ns × (1.00,1.00) -4.30% (p=0.000) RegexpMatchMedium_1K 70.3µs × (1.00,1.00) 69.5µs × (1.00,1.00) -1.13% (p=0.000) RegexpMatchHard_32 3.82µs × (1.00,1.01) 3.74µs × (1.00,1.00) -1.95% (p=0.000) RegexpMatchHard_1K 117µs × (1.00,1.00) 115µs × (1.00,1.00) -1.69% (p=0.000) Revcomp 917ms × (0.97,1.04) 920ms × (0.97,1.04) ~ (p=0.786) Template 114ms × (0.99,1.01) 117ms × (0.99,1.01) +2.58% (p=0.000) TimeParse 622ns × (0.99,1.01) 615ns × (0.99,1.00) -1.06% (p=0.000) TimeFormat 665ns × (0.99,1.01) 654ns × (0.99,1.00) -1.70% (p=0.000) This CL and previous CL (append) combined: name old mean new mean delta BinaryTree17 5.68s × (0.97,1.04) 5.71s × (0.96,1.05) ~ (p=0.638) Fannkuch11 4.41s × (0.98,1.03) 4.39s × (1.00,1.00) ~ (p=0.474) FmtFprintfEmpty 92.7ns × (0.91,1.16) 82.6ns × (0.98,1.04) -10.89% (p=0.004) FmtFprintfString 281ns × (0.96,1.08) 273ns × (0.98,1.02) ~ (p=0.078) FmtFprintfInt 288ns × (0.97,1.06) 270ns × (0.99,1.01) -6.37% (p=0.000) FmtFprintfIntInt 493ns × (0.97,1.04) 475ns × (0.99,1.01) -3.53% (p=0.002) FmtFprintfPrefixedInt 423ns × (0.97,1.04) 393ns × (1.00,1.01) -7.07% (p=0.000) FmtFprintfFloat 598ns × (0.99,1.01) 574ns × (1.00,1.01) -4.02% (p=0.000) FmtManyArgs 1.89µs × (0.98,1.05) 1.87µs × (0.99,1.02) ~ (p=0.305) GobDecode 14.8ms × (0.98,1.03) 15.0ms × (0.98,1.05) ~ (p=0.237) GobEncode 12.3ms × (0.98,1.01) 11.4ms × (0.99,1.03) -6.95% (p=0.000) Gzip 656ms × (0.99,1.05) 647ms × (0.99,1.01) ~ (p=0.101) Gunzip 142ms × (1.00,1.00) 143ms × (1.00,1.01) +0.58% (p=0.001) HTTPClientServer 91.2µs × (0.97,1.04) 88.5µs × (0.99,1.03) -3.02% (p=0.003) JSONEncode 32.6ms × (0.97,1.08) 29.6ms × (0.98,1.01) -9.10% (p=0.000) JSONDecode 114ms × (0.97,1.05) 104ms × (1.00,1.01) -8.74% (p=0.000) Mandelbrot200 6.11ms × (0.98,1.04) 6.02ms × (1.00,1.00) ~ (p=0.090) GoParse 6.66ms × (0.97,1.04) 6.37ms × (0.97,1.04) -4.41% (p=0.000) RegexpMatchEasy0_32 159ns × (0.99,1.00) 152ns × (0.99,1.01) -4.69% (p=0.000) RegexpMatchEasy0_1K 538ns × (1.00,1.01) 530ns × (1.00,1.00) -1.57% (p=0.000) RegexpMatchEasy1_32 138ns × (1.00,1.00) 134ns × (0.99,1.01) -2.91% (p=0.000) RegexpMatchEasy1_1K 869ns × (0.99,1.01) 865ns × (1.00,1.00) -0.51% (p=0.012) RegexpMatchMedium_32 252ns × (0.99,1.01) 233ns × (1.00,1.00) -7.85% (p=0.000) RegexpMatchMedium_1K 72.7µs × (1.00,1.00) 69.5µs × (1.00,1.00) -4.43% (p=0.000) RegexpMatchHard_32 3.85µs × (1.00,1.00) 3.74µs × (1.00,1.00) -2.74% (p=0.000) RegexpMatchHard_1K 118µs × (1.00,1.00) 115µs × (1.00,1.00) -2.24% (p=0.000) Revcomp 920ms × (0.97,1.07) 920ms × (0.97,1.04) ~ (p=0.998) Template 129ms × (0.98,1.03) 117ms × (0.99,1.01) -9.79% (p=0.000) TimeParse 619ns × (0.99,1.01) 615ns × (0.99,1.00) -0.57% (p=0.011) TimeFormat 661ns × (0.98,1.04) 654ns × (0.99,1.00) ~ (p=0.223) Change-Id: If054d81ab2c71d8d62cf54b5b1fac2af66b387fc Reviewed-on: https://go-review.googlesource.com/9813 Reviewed-by: David Chase <drchase@google.com> Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>		2015-05-13 19:20:39 +00:00
..
bench	build: adjustments for move from src/pkg to src	2014-09-08 00:06:45 -04:00
bugs	test: migrate remaining tests to run.go	2014-12-22 22:41:34 +00:00
chan	cmd/gc: implement 'for range x {'	2014-07-16 19:27:10 -04:00
ddd2.dir
dwarf
fixedbugs	cmd/internal/gc: avoid spurious div-zero errors	2015-05-13 17:38:13 +00:00
import2.dir
import4.dir	test: match gccgo import error messages	2013-12-12 19:02:11 -08:00
interface	cmd/internal/gc: improve "type *X has no field or method M" message	2015-05-07 16:21:57 +00:00
ken
method4.dir	cmd/gc: do not omit wrapper for expression (interface{...}).F	2014-01-07 13:26:48 +01:00
safe
stress	build: adjustments for move from src/pkg to src	2014-09-08 00:06:45 -04:00
syntax	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
64bit.go
235.go
alias1.go
alias.go
append.go
args.go
assign1.go
assign.go	cmd/gc: prohibit short variable declarations containing duplicate symbols	2014-10-06 17:16:39 -04:00
bigalg.go
bigmap.go
blank1.go	test: match gccgo error messages for blank1.go	2013-09-28 15:19:05 -07:00
blank.go	test: revert changes made for Go SSA interpreter test.	2013-10-08 14:36:20 -04:00
bom.go
bombad.go
bounds.go
chancap.go
chanlinear.go	runtime: test for linear enqueue/dequeue behavior	2014-12-08 22:18:17 +00:00
char_lit1.go
char_lit.go
clearfat.go	[dev.power64] 9g: fix under-zeroing in clearfat	2014-10-31 11:08:27 -04:00
closedchan.go
closure1.go	cmd/gc: capture variables by value	2015-01-29 13:07:30 +00:00
closure2.go	cmd/gc: fix capturing by value for range statements	2015-02-03 15:48:48 +00:00
closure.go
cmp6.go	cmd/gc: do not consider length zero arrays as comparable.	2014-01-31 00:30:56 +01:00
cmp.go	cmd/gc: do not nop-convert equivalent but different interface types.	2014-02-27 08:07:50 +01:00
cmplx.go
cmplxdivide1.go
cmplxdivide.c	test: comment the behavior and use of cmplxdivide*	2015-01-15 00:00:06 +00:00
cmplxdivide.go	test: comment the behavior and use of cmplxdivide*	2015-01-15 00:00:06 +00:00
complit1.go
complit.go
compos.go
const1.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
const2.go
const3.go
const4.go
const5.go	cmd/gc: reject builtin function calls in len(fixed array) constants	2014-04-03 19:04:33 -04:00
const6.go
const.go
convert1.go
convert3.go
convert.go
convlit1.go
convlit.go	cmd/internal/gc: unsafe.Pointer constants may only be converted to uintptr	2015-05-07 23:54:28 +00:00
convT2X.go
copy.go
crlf.go
ddd1.go
ddd2.go
ddd.go
decl.go
declbad.go
defer.go
deferfin.go	runtime: combine small NoScan allocations	2014-01-24 22:35:11 +04:00
deferprint.go
deferprint.out
divide.go
divmod.go	all: fix a few spelling errors in source comments	2013-12-27 08:59:02 -08:00
empty.go
env.go
eof1.go
eof.go
errchk
escape2.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape2n.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape3.go
escape4.go	cmd/internal/gc: transitive inlining	2015-02-26 17:36:00 +00:00
escape5.go	test: add tests for escape analysis of interface conversions	2015-03-28 16:15:27 +00:00
escape_array.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_calls.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_closure.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_field.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_iface.go	test: add tests for escape analysis of interface conversions	2015-03-28 16:15:27 +00:00
escape_indir.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_level.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_map.go	test: add tests for escape analysis of interface conversions	2015-03-28 16:15:27 +00:00
escape_param.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_slice.go	test: add tests for escape analysis of slices	2015-03-28 13:18:42 +00:00
escape_struct_param1.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_struct_param2.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_struct_return.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape.go
fibo.go	Fix whitespace (use blanks consistently).	2014-12-08 22:22:58 +00:00
float_lit2.go	test: fix two typos in float_lit2.go	2014-05-21 17:19:12 -04:00
float_lit3.go	test/float_lit2.go: rewrite to test values near boundaries	2014-05-21 17:12:06 -04:00
float_lit.go
floatcmp.go
for.go
func1.go
func2.go
func3.go
func4.go
func5.go
func6.go
func7.go
func8.go
func.go
funcdup2.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
funcdup.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
gc1.go
gc2.go	test: check for build constraints only upto the first blank line	2015-02-06 05:36:26 +00:00
gc.go
gcstring.go	runtime: fix empty string handling in garbage collector	2014-03-11 23:58:39 -04:00
goprint.go
goprint.out
goto.go
helloworld.go
helloworld.out
if.go
import1.go	test: match gccgo import error messages	2013-12-12 19:02:11 -08:00
import2.go
import4.go
import5.go
import.go
index0.go
index1.go
index2.go
index.go	test: recognize gccgo error message in index.go	2013-09-27 20:38:52 -07:00
indirect1.go
indirect.go
init1.go	test: deflake init1.go test, tighten its bounds	2015-02-13 22:13:56 +00:00
init.go
initcomma.go
initialize.go
initializerr.go
inline.go	cmd/internal/gc: transitive inlining	2015-02-26 17:36:00 +00:00
int_lit.go
intcvt.go
iota.go
label1.go
label.go
linkx_run.go	cmd/go: put user ldflags at the end of the linker invocation	2015-01-02 18:36:44 +00:00
linkx.go	test: move linkx and sinit to run.go	2014-11-06 15:14:08 -05:00
literal.go
live1.go	cmd/gc: correct liveness for fat variables	2014-02-15 10:58:55 -05:00
live2.go	cmd/gc: allocate non-escaping maps on stack	2015-02-12 09:53:52 +00:00
live.go	test: add -update_errors flag to run script	2015-04-10 11:33:42 +00:00
mallocfin.go
map1.go
map.go	test/mapnan.go: add regression test for non-empty interfaces.	2014-08-06 17:02:55 -04:00
maplinear.go	test: make maplinear more robust	2014-10-27 18:59:02 -04:00
method1.go
method2.go	cmd/gc: fix method values whose receiver is an unnamed interface.	2013-08-29 10:00:58 +02:00
method3.go
method4.go
method5.go
method.go
named1.go	cmd/gc: comma-ok assignments produce untyped bool as 2nd result	2014-08-11 16:11:55 -07:00
named.go
nil.go
nilcheck.go	cmd/gc: optimize existence-only map lookups	2015-01-07 22:36:06 +00:00
nilptr2.go	test: revert changes made for Go SSA interpreter test.	2013-10-08 14:36:20 -04:00
nilptr3.go	cmd/7g: enable peephole optimizer	2015-04-08 08:16:54 +00:00
nilptr4.go	cmd/gc: fix bad checknil with ints on 32 bit compilers	2014-02-26 12:25:13 -08:00
nilptr.go	test/nilptr: add more tests	2013-09-05 23:06:34 -04:00
nosplit.go	test: fix nosplit test for noopt build	2015-05-03 16:10:40 +00:00
nul1.go
parentype.go
peano.go
print.go	runtime: move built-in print routines to go.	2014-07-31 13:48:48 -07:00
print.out	runtime: move built-in print routines to go.	2014-07-31 13:48:48 -07:00
printbig.go
printbig.out
range.go	cmd/gc: implement 'for range x {'	2014-07-16 19:27:10 -04:00
recover1.go
recover2.go
recover3.go	tests: remove two misuses of nil pointers	2013-08-15 11:51:04 -04:00
recover4.go	test: fix recover4 test on 64kb systems	2015-03-17 05:25:01 +00:00
recover.go	test: add more cases to recover.go	2014-10-22 08:06:15 -07:00
rename1.go
rename.go
reorder2.go	cmd/gc: shorten temporary lifetimes when possible	2014-04-01 13:31:38 -04:00
reorder.go
return.go
rotate0.go	[dev.cc] test: disable rotate tests	2015-02-19 20:14:21 +00:00
rotate1.go	[dev.cc] test: disable rotate tests	2015-02-19 20:14:21 +00:00
rotate2.go	[dev.cc] test: disable rotate tests	2015-02-19 20:14:21 +00:00
rotate3.go	[dev.cc] test: disable rotate tests	2015-02-19 20:14:21 +00:00
rotate.go
run.go	test: gofmt run.go	2015-04-28 00:08:50 +00:00
rune.go
runtime.go
shift1.go	test: avoid "declared but not used" errors in shift1.go	2014-07-20 12:25:24 -07:00
shift2.go
sieve.go
sigchld.go	test: skip SIGCHLD test on Plan 9	2014-01-29 09:28:23 +01:00
sigchld.out
simassign.go
sinit_run.go	test: fix nacl build	2014-11-09 21:10:49 -05:00
sinit.go	test: move linkx and sinit to run.go	2014-11-06 15:14:08 -05:00
sizeof.go
slice3.go	cmd/gc, runtime: treat slices and strings like pointers in garbage collection	2014-08-25 14:38:19 -04:00
slice3err.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
slicecap.go	cmd/gc, runtime: treat slices and strings like pointers in garbage collection	2014-08-25 14:38:19 -04:00
sliceopt.go	cmd/internal/gc: optimize slice + write barrier	2015-05-13 19:20:39 +00:00
solitaire.go
stack.go
string_lit.go	test: add []rune case to string_lit.go	2013-12-12 17:17:02 -08:00
stringrange.go
struct0.go
switch3.go
switch4.go
switch.go
tinyfin.go	runtime: combine small NoScan allocations	2014-01-24 22:35:11 +04:00
torture.go	cmd/8g: don't allocate a register early for cap(CHAN).	2014-07-01 09:20:51 +02:00
turing.go
typecheck.go	cmd/gc: silence assignment errors to undefined symbols	2014-01-03 21:03:20 +01:00
typeswitch1.go
typeswitch2.go
typeswitch3.go
typeswitch.go
undef.go
utf.go
varerr.go
varinit.go
writebarrier.go	cmd/internal/gc: optimize append + write barrier	2015-05-12 17:55:09 +00:00
zerodivide.go