(Or(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (And(8|16|32|64) <t> x y))

// Convert multiplication by a power of two to a shift.
(Mul8  <t> n (Const8  [c])) && isPowerOfTwo8(c) => (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(c)]))
(Mul16 <t> n (Const16 [c])) && isPowerOfTwo16(c) => (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(c)]))

		return true
	}
	// match: (Div8 n (Const8 [c]))
	// cond: isNonNegative(n) && isPowerOfTwo8(c)
	// result: (Rsh8Ux64 n (Const64 <typ.UInt64> [log8(c)]))
	for {
		n := v_0
		if v_1.Op != OpConst8 {
			break
		}
		c := auxIntToInt8(v_1.AuxInt)
		if !(isNonNegative(n) && isPowerOfTwo8(c)) {
			break
		}
		v.reset(OpRsh8Ux64)
		v0 := b.NewValue0(v.Pos, OpConst64, typ.UInt64)

// Rounds down.
func log2uint32(n int64) int64 {
	return int64(bits.Len32(uint32(n))) - 1
}

// isPowerOfTwoX functions report whether n is a power of 2.
func isPowerOfTwo8(n int8) bool {
	return n > 0 && n&(n-1) == 0
}
func isPowerOfTwo16(n int16) bool {
	return n > 0 && n&(n-1) == 0
}
func isPowerOfTwo32(n int32) bool {
	return n > 0 && n&(n-1) == 0
}