// ----------------------- //

func LeadingZeros(n uint) int {
	// amd64/v1,amd64/v2:"BSRQ"
	// amd64/v3:"LZCNTQ", -"BSRQ"
	// s390x:"FLOGR"
	// arm:"CLZ" arm64:"CLZ"
	// mips:"CLZ"
	// wasm:"I64Clz"
	// ppc64x:"CNTLZD"
	return bits.LeadingZeros(n)
}

func LeadingZeros64(n uint64) int {
	// amd64/v1,amd64/v2:"BSRQ"
	// amd64/v3:"LZCNTQ", -"BSRQ"
	// s390x:"FLOGR"
	// arm:"CLZ" arm64:"CLZ"
	// mips:"CLZ"
	// wasm:"I64Clz"

	MOVQ	-8(SI)(R8*1), AX
	MOVQ	-8(DI)(R8*1), CX
	CMPQ	AX, CX
	JEQ	allsame

	// AX and CX contain parts of a and b that differ.
diff8:
	BSWAPQ	AX	// reverse order of bytes
	BSWAPQ	CX
	XORQ	AX, CX
	BSRQ	CX, CX	// index of highest bit difference
	SHRQ	CX, AX	// move a's bit to bottom
	ANDQ	$1, AX	// mask bit
	LEAQ	-1(AX*2), AX // 1/0 => +1/-1
	RET

	// 0-7 bytes in common
small:

	"BLENDPD",
	"BLENDPS",
	"BLENDVPD",
	"BLENDVPS",
	"BLSIL",
	"BLSIQ",
	"BLSMSKL",
	"BLSMSKQ",
	"BLSRL",
	"BLSRQ",
	"BOUNDL",
	"BOUNDW",
	"BSFL",
	"BSFQ",
	"BSFW",
	"BSRL",
	"BSRQ",
	"BSRW",
	"BSWAPL",
	"BSWAPQ",
	"BTCL",
	"BTCQ",
	"BTCW",
	"BTL",
	"BTQ",
	"BTRL",
	"BTRQ",
	"BTRW",
	"BTSL",
	"BTSQ",
	"BTSW",
	"BTW",
	"BYTE",
	"BZHIL",
	"BZHIQ",

// For GOAMD64>=3, BitLen can be calculated by OperandSize - LZCNT(x).
(BitLen64 <t> x) && buildcfg.GOAMD64 < 3 => (ADDQconst [1] (CMOVQEQ <t> (Select0 <t> (BSRQ x)) (MOVQconst <t> [-1]) (Select1 <types.TypeFlags> (BSRQ x))))
(BitLen32 x) && buildcfg.GOAMD64 <  3 => (Select0 (BSRQ (LEAQ1 <typ.UInt64> [1] (MOVLQZX <typ.UInt64> x) (MOVLQZX <typ.UInt64> x))))

	BSRL R11, R11                           // 450fbddb
	BSRQ (BX), DX                           // 480fbd13
	BSRQ (R11), DX                          // 490fbd13
	BSRQ DX, DX                             // 480fbdd2
	BSRQ R11, DX                            // 490fbdd3
	BSRQ (BX), R11                          // 4c0fbd1b
	BSRQ (R11), R11                         // 4d0fbd1b
	BSRQ DX, R11                            // 4c0fbdda

		{name: "BSFL", argLength: 1, reg: gp11, asm: "BSFL", typ: "UInt32", clobberFlags: true}, // # of low-order zeroes in 32-bit arg
		{name: "BSRQ", argLength: 1, reg: gp11flags, asm: "BSRQ", typ: "(UInt64,Flags)"},        // # of high-order zeroes in 64-bit arg
		{name: "BSRL", argLength: 1, reg: gp11, asm: "BSRL", typ: "UInt32", clobberFlags: true}, // # of high-order zeroes in 32-bit arg

	v_0 := v.Args[0]
	b := v.Block
	typ := &b.Func.Config.Types
	// match: (BitLen64 <t> x)
	// cond: buildcfg.GOAMD64 < 3
	// result: (ADDQconst [1] (CMOVQEQ <t> (Select0 <t> (BSRQ x)) (MOVQconst <t> [-1]) (Select1 <types.TypeFlags> (BSRQ x))))
	for {
		t := v.Type
		x := v_0
		if !(buildcfg.GOAMD64 < 3) {
			break
		}
		v.reset(OpAMD64ADDQconst)
		v.AuxInt = int32ToAuxInt(1)

			},
			outputs: []outputInfo{
				{0, 49135}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
			},
		},
	},
	{
		name:   "BSRQ",
		argLen: 1,
		asm:    x86.ABSRQ,
		reg: regInfo{
			inputs: []inputInfo{
				{0, 49135}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R15
			},
			outputs: []outputInfo{
				{1, 0},