Josh Bleecher Snyder 638ebb04f2 cmd/compile: don't break up contiguous blocks in looprotate ... looprotate finds loop headers and arranges for them to be placed after the body of the loop. This eliminates a jump from the body. However, if the loop header is a series of contiguously laid out blocks, the rotation introduces a new jump in that series. This CL expands the "loop header" to move to be the entire run of contiguously laid out blocks in the same loop. This shrinks object files a little, and actually speeds up the compiler noticeably. Numbers below. Fannkuch performance seems to vary a lot by machine. On my laptop: name old time/op new time/op delta Fannkuch11-8 2.89s ± 2% 2.85s ± 3% -1.22% (p=0.000 n=50+50) This has a significant affect on the append benchmarks in #14758: name old time/op new time/op delta Foo-8 312ns ± 3% 276ns ± 2% -11.37% (p=0.000 n=30+29) Bar-8 565ns ± 2% 456ns ± 2% -19.27% (p=0.000 n=27+28) Updates #18977 Fixes #20355 name old time/op new time/op delta Template 205ms ± 5% 204ms ± 8% ~ (p=0.903 n=92+99) Unicode 85.3ms ± 4% 85.1ms ± 3% ~ (p=0.191 n=92+94) GoTypes 512ms ± 4% 507ms ± 4% -0.93% (p=0.000 n=95+97) Compiler 2.38s ± 3% 2.35s ± 3% -1.27% (p=0.000 n=98+95) SSA 4.67s ± 3% 4.64s ± 3% -0.62% (p=0.000 n=95+96) Flate 117ms ± 3% 117ms ± 3% ~ (p=0.099 n=84+86) GoParser 139ms ± 4% 137ms ± 4% -0.90% (p=0.000 n=97+98) Reflect 329ms ± 5% 326ms ± 6% -0.97% (p=0.002 n=99+98) Tar 102ms ± 6% 101ms ± 5% -0.97% (p=0.006 n=97+97) XML 198ms ±10% 196ms ±13% ~ (p=0.087 n=100+100) [Geo mean] 318ms 316ms -0.72% name old user-time/op new user-time/op delta Template 250ms ± 7% 250ms ± 7% ~ (p=0.850 n=94+92) Unicode 107ms ± 8% 106ms ± 5% -0.76% (p=0.005 n=98+91) GoTypes 665ms ± 5% 659ms ± 5% -0.85% (p=0.003 n=93+98) Compiler 3.15s ± 3% 3.10s ± 3% -1.60% (p=0.000 n=99+98) SSA 6.82s ± 3% 6.72s ± 4% -1.55% (p=0.000 n=94+98) Flate 138ms ± 8% 138ms ± 6% ~ (p=0.369 n=94+92) GoParser 170ms ± 5% 168ms ± 6% -1.13% (p=0.002 n=96+98) Reflect 412ms ± 8% 416ms ± 8% ~ (p=0.169 n=100+100) Tar 123ms ±18% 123ms ±14% ~ (p=0.896 n=100+100) XML 236ms ± 9% 234ms ±11% ~ (p=0.124 n=100+100) [Geo mean] 401ms 398ms -0.63% name old alloc/op new alloc/op delta Template 38.8MB ± 0% 38.8MB ± 0% ~ (p=0.222 n=5+5) Unicode 28.7MB ± 0% 28.7MB ± 0% ~ (p=0.421 n=5+5) GoTypes 109MB ± 0% 109MB ± 0% ~ (p=0.056 n=5+5) Compiler 457MB ± 0% 457MB ± 0% +0.07% (p=0.008 n=5+5) SSA 1.10GB ± 0% 1.10GB ± 0% +0.05% (p=0.008 n=5+5) Flate 24.5MB ± 0% 24.5MB ± 0% ~ (p=0.222 n=5+5) GoParser 30.9MB ± 0% 31.0MB ± 0% +0.21% (p=0.016 n=5+5) Reflect 73.4MB ± 0% 73.4MB ± 0% ~ (p=0.421 n=5+5) Tar 25.5MB ± 0% 25.5MB ± 0% ~ (p=0.548 n=5+5) XML 40.9MB ± 0% 40.9MB ± 0% ~ (p=0.151 n=5+5) [Geo mean] 71.6MB 71.6MB +0.07% name old allocs/op new allocs/op delta Template 394k ± 0% 394k ± 0% ~ (p=1.000 n=5+5) Unicode 344k ± 0% 343k ± 0% ~ (p=0.310 n=5+5) GoTypes 1.16M ± 0% 1.16M ± 0% ~ (p=1.000 n=5+5) Compiler 4.42M ± 0% 4.42M ± 0% ~ (p=1.000 n=5+5) SSA 9.80M ± 0% 9.80M ± 0% ~ (p=0.095 n=5+5) Flate 237k ± 1% 238k ± 1% ~ (p=0.310 n=5+5) GoParser 320k ± 0% 322k ± 1% +0.50% (p=0.032 n=5+5) Reflect 958k ± 0% 957k ± 0% ~ (p=0.548 n=5+5) Tar 252k ± 1% 252k ± 0% ~ (p=1.000 n=5+5) XML 400k ± 0% 400k ± 0% ~ (p=0.841 n=5+5) [Geo mean] 741k 742k +0.06% name old object-bytes new object-bytes delta Template 386k ± 0% 386k ± 0% -0.05% (p=0.008 n=5+5) Unicode 202k ± 0% 202k ± 0% -0.01% (p=0.008 n=5+5) GoTypes 1.16M ± 0% 1.16M ± 0% -0.06% (p=0.008 n=5+5) Compiler 3.91M ± 0% 3.91M ± 0% -0.06% (p=0.008 n=5+5) SSA 7.91M ± 0% 7.92M ± 0% +0.01% (p=0.008 n=5+5) Flate 228k ± 0% 227k ± 0% -0.04% (p=0.008 n=5+5) GoParser 283k ± 0% 283k ± 0% -0.06% (p=0.008 n=5+5) Reflect 952k ± 0% 951k ± 0% -0.02% (p=0.008 n=5+5) Tar 187k ± 0% 187k ± 0% -0.04% (p=0.008 n=5+5) XML 406k ± 0% 406k ± 0% -0.05% (p=0.008 n=5+5) [Geo mean] 648k 648k -0.04% Change-Id: I8630c4291a0eb2f7e7927bc04d7cc0efef181094 Reviewed-on: https://go-review.googlesource.com/43491 Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>		2017-05-18 17:58:39 +00:00
..
addr2line	cmd/go: build test binaries with -s in addition to -w	2017-03-29 17:18:16 +00:00
api	api: promote next.txt to go1.8.txt, update go tool	2016-12-01 02:54:21 +00:00
asm	cmd/internal/obj/arm: remove illegal form of the SWI instruction	2017-05-18 13:38:13 +00:00
cgo	cmd/cgo: support large unsigned macros	2017-05-17 14:42:29 +00:00
compile	cmd/compile: don't break up contiguous blocks in looprotate	2017-05-18 17:58:39 +00:00
cover	cmd/cover: fix spelling mistake	2016-12-20 04:45:25 +00:00
dist	internal/cpu: new package to detect cpu features	2017-05-10 17:02:21 +00:00
doc	cmd/doc: implement "go doc struct.field"	2017-03-22 05:37:50 +00:00
fix	cmd/fix,cmd/gofmt: flush to disk before diffing	2017-03-30 18:19:57 +00:00
go	cmd/go: don't fail on missing runtime/internal/sys/zversion.go	2017-05-17 01:30:51 +00:00
gofmt	cmd/fix,cmd/gofmt: flush to disk before diffing	2017-03-30 18:19:57 +00:00
internal	cmd/internal/obj/arm: remove illegal form of the SWI instruction	2017-05-18 13:38:13 +00:00
link	cmd/link: make sure that runtime.epclntab lives in .text section	2017-05-18 05:32:41 +00:00
nm	all: fix some printf format strings	2017-02-14 02:09:30 +00:00
objdump	cmd/internal/objabi: fix the bug of shrinking SymType down to a uint8	2017-05-16 12:26:10 +00:00
pack	all: use testing.GoToolPath instead of "go"	2016-08-30 22:49:11 +00:00
pprof	cmd/pprof: update README to explain relationship with github.com/google/pprof	2017-04-10 19:51:01 +00:00
trace	cmd/trace: document that trace viewer is only tested on chromium	2017-04-20 16:44:55 +00:00
vendor	cmd/vendor/arch/x86: pull new version from x repo	2017-04-20 22:39:48 +00:00
vet	internal/cpu: new package to detect cpu features	2017-05-10 17:02:21 +00:00