// result: mem
	for {
		if v_0.Op != OpSelectN || auxIntToInt64(v_0.AuxInt) != 0 {
			break
		}
		call := v_0.Args[0]
		if call.Op != OpStaticLECall || len(call.Args) != 2 {
			break
		}
		x := v_1
		mem := v_2

	case OpRsh8x8:
		return rewriteValueARM64_OpRsh8x8(v)
	case OpSelect0:
		return rewriteValueARM64_OpSelect0(v)
	case OpSelect1:
		return rewriteValueARM64_OpSelect1(v)
	case OpSelectN:
		return rewriteValueARM64_OpSelectN(v)
	case OpSignExt16to32:
		v.Op = OpARM64MOVHreg
		return true
	case OpSignExt16to64:
		v.Op = OpARM64MOVHreg
		return true
	case OpSignExt32to64:

	case OpRsh8x8:
		return rewriteValueAMD64_OpRsh8x8(v)
	case OpSelect0:
		return rewriteValueAMD64_OpSelect0(v)
	case OpSelect1:
		return rewriteValueAMD64_OpSelect1(v)
	case OpSelectN:
		return rewriteValueAMD64_OpSelectN(v)
	case OpSignExt16to32:
		v.Op = OpAMD64MOVWQSX
		return true
	case OpSignExt16to64:
		v.Op = OpAMD64MOVWQSX
		return true
	case OpSignExt32to64: