Benchhmarking Bounds Checking of Slices

Benchmark Results

BenchmarkBoundsCheckRawLoop   	  200000	      8782 ns/op	       0 B/op	       0 allocs/op
BenchmarkBoundsCheckRangeIndex	  200000	      9553 ns/op	       0 B/op	       0 allocs/op
BenchmarkBoundsCheckRangeVal  	  200000	      8648 ns/op	       0 B/op	       0 allocs/op

bounds_test.go

package code

import (
	"testing"
)

var y = 0
var bvalues = makeIntSlice(4000)

func makeIntSlice(n int) []int {
	r := make([]int, n)
	for i := 0; i < n; i++ {
		r[i] = i
	}
	return r
}

func BoundsCheckRawLoop() {
	for i := 0; i < len(bvalues); i++ {
		y += bvalues[i]
	}
}

func BoundsCheckRangeIndex() {
	for i := range bvalues {
		y += bvalues[i]
	}
}

func BoundsCheckRangeVal() {
	for _, i := range bvalues {
		y += i
	}
}

func BenchmarkBoundsCheckRawLoop(b *testing.B) {
	for i := 0; i < b.N; i++ {
		BoundsCheckRawLoop()
	}
}

func BenchmarkBoundsCheckRangeIndex(b *testing.B) {
	for i := 0; i < b.N; i++ {
		BoundsCheckRangeIndex()
	}
}

func BenchmarkBoundsCheckRangeVal(b *testing.B) {
	for i := 0; i < b.N; i++ {
		BoundsCheckRangeVal()
	}
}

xx BoundsCheckRangeIndex Assembly

	0x0000 00000 (bounds.go:21)	TEXT	"".BoundsCheckRangeIndex+0(SB),$0-0
	0x0000 00000 (bounds.go:21)	MOVQ	(TLS),CX
	0x0009 00009 (bounds.go:21)	CMPQ	SP,16(CX)
	0x000d 00013 (bounds.go:21)	JHI	,22
	0x000f 00015 (bounds.go:21)	CALL	,runtime.morestack_noctxt(SB)
	0x0014 00020 (bounds.go:21)	JMP	,0
	0x0016 00022 (bounds.go:21)	NOP	,
	0x0016 00022 (bounds.go:21)	NOP	,
	0x0016 00022 (bounds.go:21)	FUNCDATA	$0,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0016 00022 (bounds.go:21)	FUNCDATA	$1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0016 00022 (bounds.go:22)	MOVQ	"".bvalues+8(SB),SI
	0x001d 00029 (bounds.go:22)	MOVQ	$0,AX
	0x001f 00031 (bounds.go:22)	CMPQ	AX,SI
	0x0022 00034 (bounds.go:22)	JGE	$0,87
	0x0024 00036 (bounds.go:23)	MOVQ	"".y+0(SB),CX
	0x002b 00043 (bounds.go:23)	MOVQ	"".bvalues+0(SB),BX
	0x0032 00050 (bounds.go:23)	MOVQ	"".bvalues+8(SB),R8
	0x0039 00057 (bounds.go:23)	CMPQ	AX,R8
	0x003c 00060 (bounds.go:23)	JCC	$1,88
	0x003e 00062 (bounds.go:23)	LEAQ	(BX)(AX*8),BX
	0x0042 00066 (bounds.go:23)	MOVQ	(BX),BX
	0x0045 00069 (bounds.go:23)	ADDQ	CX,BX
	0x0048 00072 (bounds.go:23)	MOVQ	BX,"".y+0(SB)
	0x004f 00079 (bounds.go:23)	NOP	,
	0x004f 00079 (bounds.go:22)	INCQ	,AX
	0x0052 00082 (bounds.go:22)	CMPQ	AX,SI
	0x0055 00085 (bounds.go:22)	JLT	$0,36
	0x0057 00087 (bounds.go:25)	RET	,
	0x0058 00088 (bounds.go:23)	PCDATA	$0,$0
	0x0058 00088 (bounds.go:23)	CALL	,runtime.panicindex(SB)
	0x005d 00093 (bounds.go:23)	UNDEF	,

xx BoundsCheckRangeVal Assembly

	0x0000 00000 (bounds.go:27)	TEXT	"".BoundsCheckRangeVal+0(SB),4,$0-0
	0x0000 00000 (bounds.go:27)	NOP	,
	0x0000 00000 (bounds.go:27)	NOP	,
	0x0000 00000 (bounds.go:27)	FUNCDATA	$0,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0000 00000 (bounds.go:27)	FUNCDATA	$1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0000 00000 (bounds.go:28)	NOP	,
	0x0000 00000 (bounds.go:28)	MOVQ	"".bvalues+0(SB),AX
	0x0007 00007 (bounds.go:28)	MOVQ	"".bvalues+8(SB),SI
	0x000e 00014 (bounds.go:28)	MOVQ	"".bvalues+16(SB),BX
	0x0015 00021 (bounds.go:28)	MOVQ	$0,CX
	0x0017 00023 (bounds.go:28)	CMPQ	CX,SI
	0x001a 00026 (bounds.go:28)	JGE	$0,60
	0x001c 00028 (bounds.go:28)	NOP	,
	0x001c 00028 (bounds.go:28)	MOVQ	(AX),DX
	0x001f 00031 (bounds.go:29)	MOVQ	"".y+0(SB),BX
	0x0026 00038 (bounds.go:29)	ADDQ	DX,BX
	0x0029 00041 (bounds.go:29)	MOVQ	BX,"".y+0(SB)
	0x0030 00048 (bounds.go:29)	NOP	,
	0x0030 00048 (bounds.go:28)	ADDQ	$8,AX
	0x0034 00052 (bounds.go:28)	INCQ	,CX
	0x0037 00055 (bounds.go:28)	CMPQ	CX,SI
	0x003a 00058 (bounds.go:28)	JLT	$0,28
	0x003c 00060 (bounds.go:28)	NOP	,
	0x003c 00060 (bounds.go:31)	RET	,

xx BoundsCheckRawLoop Assembly

	0x0000 00000 (bounds.go:15)	TEXT	"".BoundsCheckRawLoop+0(SB),$0-0
	0x0000 00000 (bounds.go:15)	MOVQ	(TLS),CX
	0x0009 00009 (bounds.go:15)	CMPQ	SP,16(CX)
	0x000d 00013 (bounds.go:15)	JHI	,22
	0x000f 00015 (bounds.go:15)	CALL	,runtime.morestack_noctxt(SB)
	0x0014 00020 (bounds.go:15)	JMP	,0
	0x0016 00022 (bounds.go:15)	NOP	,
	0x0016 00022 (bounds.go:15)	NOP	,
	0x0016 00022 (bounds.go:15)	FUNCDATA	$0,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0016 00022 (bounds.go:15)	FUNCDATA	$1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
	0x0016 00022 (bounds.go:16)	MOVQ	$0,AX
	0x0018 00024 (bounds.go:16)	MOVQ	"".bvalues+8(SB),CX
	0x001f 00031 (bounds.go:16)	CMPQ	AX,CX
	0x0022 00034 (bounds.go:16)	JGE	$0,94
	0x0024 00036 (bounds.go:16)	NOP	,
	0x0024 00036 (bounds.go:17)	MOVQ	"".y+0(SB),CX
	0x002b 00043 (bounds.go:17)	MOVQ	"".bvalues+0(SB),BX
	0x0032 00050 (bounds.go:17)	MOVQ	"".bvalues+8(SB),R8
	0x0039 00057 (bounds.go:17)	CMPQ	AX,R8
	0x003c 00060 (bounds.go:17)	JCC	$1,95
	0x003e 00062 (bounds.go:17)	LEAQ	(BX)(AX*8),BX
	0x0042 00066 (bounds.go:17)	MOVQ	(BX),BX
	0x0045 00069 (bounds.go:17)	ADDQ	CX,BX
	0x0048 00072 (bounds.go:17)	MOVQ	BX,"".y+0(SB)
	0x004f 00079 (bounds.go:17)	NOP	,
	0x004f 00079 (bounds.go:16)	INCQ	,AX
	0x0052 00082 (bounds.go:16)	NOP	,
	0x0052 00082 (bounds.go:16)	MOVQ	"".bvalues+8(SB),CX
	0x0059 00089 (bounds.go:16)	CMPQ	AX,CX
	0x005c 00092 (bounds.go:16)	JLT	$0,36
	0x005e 00094 (bounds.go:16)	NOP	,
	0x005e 00094 (bounds.go:19)	RET	,
	0x005f 00095 (bounds.go:17)	PCDATA	$0,$0
	0x005f 00095 (bounds.go:17)	CALL	,runtime.panicindex(SB)
	0x0064 00100 (bounds.go:17)	UNDEF	,