v_1 := v.Args[1]
	v_0 := v.Args[0]
	b := v.Block
	typ := &b.Func.Config.Types
	// match: (Rsh8x16 <t> x y)
	// cond: shiftIsBounded(v)
	// result: (SRA <t> (SignExt8to64 x) y)
	for {
		t := v.Type
		x := v_0
		y := v_1
		if !(shiftIsBounded(v)) {
			break
		}
		v.reset(OpARM64SRA)
		v.Type = t

	v_0 := v.Args[0]
	// match: (SignExt8to64 (Const8 [c]))
	// result: (Const64 [int64(c)])
	for {
		if v_0.Op != OpConst8 {
			break
		}
		c := auxIntToInt8(v_0.AuxInt)
		v.reset(OpConst64)
		v.AuxInt = int64ToAuxInt(int64(c))
		return true
	}
	// match: (SignExt8to64 (Trunc64to8 x:(Rsh64x64 _ (Const64 [s]))))
	// cond: s >= 56
	// result: x