return "types.Types[types.TUNSAFEPTR]"

	case *ast.ArrayType:
		if t.Len == nil {
			return fmt.Sprintf("types.NewSlice(%s)", i.subtype(t.Elt))
		}
		return fmt.Sprintf("types.NewArray(%s, %d)", i.subtype(t.Elt), intconst(t.Len))
	case *ast.ChanType:
		dir := "types.Cboth"
		switch t.Dir {
		case ast.SEND:
			dir = "types.Csend"
		case ast.RECV:
			dir = "types.Crecv"
		}

	var thenList []syntax.Stmt
	if zeroNext {
		clr := &syntax.AssignStmt{
			Lhs: r.next(),
			Rhs: r.intConst(0),
		}
		thenList = append(thenList, clr)
	}
	for _, then := range thens {
		thenList = append(thenList, then)
	}
	nif := &syntax.IfStmt{
		Cond: r.cond(op, r.next(), r.intConst(c)),
		Then: &syntax.BlockStmt{
			List: thenList,
		},
	}
	return nif
}

	I32Load8S $0
	Tee R4
	I32Eq
	If
	Get R0
	I32Const $1
	I32Add
	Set R0
	Get R1
	I32Const $1
	I32Add
	Set R1
	I32Const $0
	Get R2
	I32Const $-1
	I32Add
	Tee R2
	I32Eqz
	BrIf $3
	Drop
	Br $1
	End
	End
	Get R3
	I32Const $255
	I32And
	Get R4
	I32Const $255
	I32And
	I32Sub
	Else
	I32Const $0
	End

	Set R4
	Block
		Block
			Get R2
			I32Const $0
			I32Ne
			Tee R3
			Get R0
			I32Const $3
			I32And
			I32Const $0
			I32Ne
			I32And
			If
				Loop
					Get R0
					I32Load8U $0
					Get R1
					I32Eq
					BrIf $2
					Get R2
					I32Const $-1
					I32Add
					Tee R2
					I32Const $0
					I32Ne
					Tee R3
					Get R0
					I32Const $1
					I32Add
					Tee R0

	I64Const $8
	Call	gcWriteBarrier<>(SB)
	Return
TEXT runtime·gcWriteBarrier2<ABIInternal>(SB),NOSPLIT,$0
	I64Const $16
	Call	gcWriteBarrier<>(SB)
	Return
TEXT runtime·gcWriteBarrier3<ABIInternal>(SB),NOSPLIT,$0
	I64Const $24
	Call	gcWriteBarrier<>(SB)
	Return
TEXT runtime·gcWriteBarrier4<ABIInternal>(SB),NOSPLIT,$0
	I64Const $32
	Call	gcWriteBarrier<>(SB)
	Return

		"v20",
	}

	parse := func(s string) (n int, isconst bool) {
		if s == "vminus1" {
			return -1, false
		}
		isconst = true
		if s[0] == 'v' {
			isconst = false
			s = s[1:]
		}
		n, _ = strconv.Atoi(s)
		return n, isconst
	}

	const Cap = 10 // cap of slice, array

	for _, base := range []string{"array", "slice"} {
		for _, i := range index {
			iv, iconst := parse(i)
			for _, j := range index {

// fold extensions and ANDs together
(MOVBUreg (ANDconst [c] x)) => (ANDconst [c&0xff] x)
(MOVHUreg (ANDconst [c] x)) => (ANDconst [c&0xffff] x)
(MOVBreg (ANDconst [c] x)) && c & 0x80   == 0 => (ANDconst [c&0x7f] x)
(MOVHreg (ANDconst [c] x)) && c & 0x8000 == 0 => (ANDconst [c&0x7fff] x)

// don't extend before store

(SGTconst [c] (MOVBUreg _)) && 0xff < c => (MOVVconst [1])
(SGTconst [c] (MOVBUreg _)) && c < 0 => (MOVVconst [0])
(SGTUconst [c] (MOVBUreg _)) && 0xff < uint64(c) => (MOVVconst [1])
(SGTconst [c] (MOVHreg _)) && 0x7fff < c => (MOVVconst [1])
(SGTconst [c] (MOVHreg _)) && c <= -0x8000 => (MOVVconst [0])
(SGTconst [c] (MOVHUreg _)) && 0xffff < c => (MOVVconst [1])
(SGTconst [c] (MOVHUreg _)) && c < 0 => (MOVVconst [0])

(SGTconst [c] (MOVBUreg _)) && 0xff < c => (MOVVconst [1])
(SGTconst [c] (MOVBUreg _)) && c < 0 => (MOVVconst [0])
(SGTUconst [c] (MOVBUreg _)) && 0xff < uint64(c) => (MOVVconst [1])
(SGTconst [c] (MOVHreg _)) && 0x7fff < c => (MOVVconst [1])
(SGTconst [c] (MOVHreg _)) && c <= -0x8000 => (MOVVconst [0])
(SGTconst [c] (MOVHUreg _)) && 0xffff < c => (MOVVconst [1])
(SGTconst [c] (MOVHUreg _)) && c < 0 => (MOVVconst [0])

	"I64Load32U",
	"I32Store",
	"I64Store",
	"F32Store",
	"F64Store",
	"I32Store8",
	"I32Store16",
	"I64Store8",
	"I64Store16",
	"I64Store32",
	"CurrentMemory",
	"GrowMemory",
	"I32Const",
	"I64Const",
	"F32Const",
	"F64Const",
	"I32Eqz",
	"I32Eq",
	"I32Ne",
	"I32LtS",
	"I32LtU",
	"I32GtS",
	"I32GtU",
	"I32LeS",
	"I32LeU",
	"I32GeS",
	"I32GeU",
	"I64Eqz",
	"I64Eq",