panic("fail")
	}

	x =
		len(a0) +
			len(a2)
	if x != 20 {
		println("wrong arraylen")
		panic("fail")
	}

	x =
		len(b0) +
			len(b3)
	if x != 3 {
		println("wrong slicelen")
		panic("fail")
	}

	x =
		cap(b0) +
			cap(b3)
	if x != 3 {
		println("wrong slicecap")
		panic("fail")
	}
}

(Store dst (StringMake ptr len) mem) =>
  (Store {typ.Int}
    (OffPtr <typ.IntPtr> [config.PtrSize] dst)
    len
    (Store {typ.BytePtr} dst ptr mem))

// slice ops
(SlicePtr (SliceMake ptr _ _ )) => ptr
(SliceLen (SliceMake _ len _)) => len
(SliceCap (SliceMake _ _ cap)) => cap
(SlicePtrUnchecked (SliceMake ptr _ _ )) => ptr

(Load <t> ptr mem) && t.IsSlice() =>
  (SliceMake
    (Load <t.Elem().PtrTo()> ptr mem)

// a more comprehensive set.
(SliceLen (SliceMake _ (Const64 <t> [c]) _)) => (Const64 <t> [c])
(SliceCap (SliceMake _ _ (Const64 <t> [c]))) => (Const64 <t> [c])
(SliceLen (SliceMake _ (Const32 <t> [c]) _)) => (Const32 <t> [c])
(SliceCap (SliceMake _ _ (Const32 <t> [c]))) => (Const32 <t> [c])
(SlicePtr (SliceMake (SlicePtr x) _ _)) => (SlicePtr x)
(SliceLen (SliceMake _ (SliceLen x) _)) => (SliceLen x)

	v_0 := v.Args[0]
	b := v.Block
	config := b.Func.Config
	typ := &b.Func.Config.Types
	// match: (SliceLen (SliceMake _ len _))
	// result: len
	for {
		if v_0.Op != OpSliceMake {
			break
		}
		len := v_0.Args[1]
		v.copyOf(len)
		return true
	}
	// match: (SliceLen x:(Load <t> ptr mem))
	// cond: t.IsSlice()
	// result: @x.Block (Load <typ.Int> (OffPtr <typ.IntPtr> [config.PtrSize] ptr) mem)

	// Slices
	{name: "SliceMake", argLength: 3},                // arg0=ptr, arg1=len, arg2=cap
	{name: "SlicePtr", argLength: 1, typ: "BytePtr"}, // ptr(arg0)
	{name: "SliceLen", argLength: 1},                 // len(arg0)
	{name: "SliceCap", argLength: 1},                 // cap(arg0)
	// SlicePtrUnchecked, like SlicePtr, extracts the pointer from a slice.

		c := auxIntToInt32(v_0_1.AuxInt)
		v.reset(OpConst32)
		v.Type = t
		v.AuxInt = int32ToAuxInt(c)
		return true
	}
	// match: (SliceLen (SliceMake _ (SliceLen x) _))
	// result: (SliceLen x)
	for {
		if v_0.Op != OpSliceMake {
			break
		}
		_ = v_0.Args[1]
		v_0_1 := v_0.Args[1]
		if v_0_1.Op != OpSliceLen {
			break
		}
		x := v_0_1.Args[0]
		v.reset(OpSliceLen)

	},
	{
		name:    "SliceMake",
		argLen:  3,
		generic: true,
	},
	{
		name:    "SlicePtr",
		argLen:  1,
		generic: true,
	},
	{
		name:    "SliceLen",
		argLen:  1,
		generic: true,
	},
	{
		name:    "SliceCap",
		argLen:  1,
		generic: true,
	},
	{
		name:    "SlicePtrUnchecked",
		argLen:  1,