(MUL x (MOVDconst [1])) => x
(MUL x (MOVDconst [c])) && isPowerOfTwo64(c) => (SLLconst [log64(c)] x)
(MUL x (MOVDconst [c])) && isPowerOfTwo64(c-1) && c >= 3 => (ADDshiftLL x x [log64(c-1)])
(MUL x (MOVDconst [c])) && isPowerOfTwo64(c+1) && c >= 7 => (ADDshiftLL (NEG <x.Type> x) x [log64(c+1)])
(MUL x (MOVDconst [c])) && c%3 == 0 && isPowerOfTwo64(c/3) => (SLLconst [log64(c/3)] (ADDshiftLL <x.Type> x x [1]))

	// amd64/v3:"BLSRL"
	return x & (x - 1)
}

func isPowerOfTwo64(x int64) bool {
	// amd64/v3:"BLSRQ",-"TESTQ",-"CALL"
	return blsr64(x) == 0
}

func isPowerOfTwo32(x int32) bool {
	// amd64/v3:"BLSRL",-"TESTL",-"CALL"
	return blsr32(x) == 0
}

func isPowerOfTwoSelect64(x, a, b int64) int64 {
	var r int64
	// amd64/v3:"BLSRQ",-"TESTQ",-"CALL"
	if isPowerOfTwo64(x) {
		r = a
	} else {
		r = b
	}

		v.AddArg2(a, x)
		return true
	}
	// match: (MADD a x (MOVDconst [c]))
	// cond: isPowerOfTwo64(c)
	// result: (ADDshiftLL a x [log64(c)])
	for {
		a := v_0
		x := v_1
		if v_2.Op != OpARM64MOVDconst {
			break
		}
		c := auxIntToInt64(v_2.AuxInt)
		if !(isPowerOfTwo64(c)) {
			break
		}
		v.reset(OpARM64ADDshiftLL)
		v.AuxInt = int64ToAuxInt(log64(c))

(MULV x (MOVVconst [1])) => x
(MULV x (MOVVconst [c])) && isPowerOfTwo64(c) => (SLLVconst [log64(c)] x)

// div by constant
(DIVVU x (MOVVconst [1])) => x
(DIVVU x (MOVVconst [c])) && isPowerOfTwo64(c) => (SRLVconst [log64(c)] x)
(REMVU _ (MOVVconst [1])) => (MOVVconst [0])                       // mod
(REMVU x (MOVVconst [c])) && isPowerOfTwo64(c) => (ANDconst [c-1] x) // mod

// generic simplifications

(Select1 (MULTU (MOVWconst [c])  x )) && isPowerOfTwo64(int64(uint32(c))) => (SLLconst [int32(log2uint32(int64(c)))] x)
(Select0 (MULTU (MOVWconst [c])  x )) && isPowerOfTwo64(int64(uint32(c))) => (SRLconst [int32(32-log2uint32(int64(c)))] x)

(MUL (MOVWconst [0])  _ ) => (MOVWconst [0])
(MUL (MOVWconst [1])  x ) => x
(MUL (MOVWconst [-1]) x ) => (NEG x)

(Select1 (MULVU x (MOVVconst [c]))) && isPowerOfTwo64(c) => (SLLVconst [log64(c)] x)

// div by constant
(Select1 (DIVVU x (MOVVconst [1]))) => x
(Select1 (DIVVU x (MOVVconst [c]))) && isPowerOfTwo64(c) => (SRLVconst [log64(c)] x)
(Select0 (DIVVU _ (MOVVconst [1]))) => (MOVVconst [0])                       // mod
(Select0 (DIVVU x (MOVVconst [c]))) && isPowerOfTwo64(c) => (ANDconst [c-1] x) // mod

// generic simplifications

(Mul16 <t> n (Const16 [c])) && isPowerOfTwo16(c) => (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(c)]))
(Mul32 <t> n (Const32 [c])) && isPowerOfTwo32(c) => (Lsh32x64 <t> n (Const64 <typ.UInt64> [log32(c)]))
(Mul64 <t> n (Const64 [c])) && isPowerOfTwo64(c) => (Lsh64x64 <t> n (Const64 <typ.UInt64> [log64(c)]))
(Mul8  <t> n (Const8  [c])) && t.IsSigned() && isPowerOfTwo8(-c)  => (Neg8  (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(-c)])))

			break
		}
		v.copyOf(x)
		return true
	}
	// match: (DIVVU x (MOVVconst [c]))
	// cond: isPowerOfTwo64(c)
	// result: (SRLVconst [log64(c)] x)
	for {
		x := v_0
		if v_1.Op != OpLOONG64MOVVconst {
			break
		}
		c := auxIntToInt64(v_1.AuxInt)
		if !(isPowerOfTwo64(c)) {
			break
		}
		v.reset(OpLOONG64SRLVconst)
		v.AuxInt = int64ToAuxInt(log64(c))
		v.AddArg(x)

		}
		break
	}
	// match: (MUL (MOVWconst [c]) x )
	// cond: isPowerOfTwo64(int64(uint32(c)))
	// result: (SLLconst [int32(log2uint32(int64(c)))] x)
	for {
		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
			if v_0.Op != OpMIPSMOVWconst {
				continue
			}
			c := auxIntToInt32(v_0.AuxInt)
			x := v_1
			if !(isPowerOfTwo64(int64(uint32(c)))) {
				continue
			}
			v.reset(OpMIPSSLLconst)

	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
}
func isPowerOfTwo64(n int64) bool {
	return n > 0 && n&(n-1) == 0
}

// isUint64PowerOfTwo reports whether uint64(n) is a power of 2.
func isUint64PowerOfTwo(in int64) bool {
	n := uint64(in)
	return n > 0 && n&(n-1) == 0