RotateRight      Shift = 3 // right rotate
	RotateRightExt   Shift = 4 // right rotate through carry (Count will always be 1)
)

var shiftName = [...]string{
	"LSL", "LSR", "ASR", "ROR", "RRX",
}

func (s Shift) String() string {
	if s < 5 {
		return shiftName[s]
	}
	return fmt.Sprintf("Shift(%d)", int(s))
}

// A RegShift is a register shifted by a constant.
type RegShift struct {
	Reg   Reg

	// Check that all the shift/trunc are of the same base value.
	shiftBase := getShiftBase(a)
	if shiftBase == nil {
		return false
	}
	for i := int64(0); i < n; i++ {
		if !isShiftBase(a[i].store, shiftBase) {
			return false
		}
	}

	// Check for writes in little-endian or big-endian order.
	isLittleEndian := true
	shift0 := shift(a[0].store, shiftBase)
	for i := int64(1); i < n; i++ {