// byte order ord.
func Decode(src []byte, ord binary.ByteOrder) (inst Inst, err error) {
	if len(src) < 4 {
		return inst, errShort
	}
	if decoderCover == nil {
		decoderCover = make([]bool, len(instFormats))
	}
	inst.Len = 4
	ui_extn := [2]uint32{ord.Uint32(src[:inst.Len]), 0}
	ui := uint64(ui_extn[0]) << 32
	inst.Enc = ui_extn[0]
	opcode := inst.Enc >> 26
	if opcode == prefixOpcode {

		}
		return f
	}
	panic("regexp: unhandled case in compile")
}

func (c *compiler) inst(op InstOp) frag {
	// TODO: impose length limit
	f := frag{i: uint32(len(c.p.Inst)), nullable: true}
	c.p.Inst = append(c.p.Inst, Inst{Op: op})
	return f
}

func (c *compiler) nop() frag {
	f := c.inst(InstNop)
	f.out = makePatchList(f.i << 1)
	return f
}

func (c *compiler) fail() frag {

	if inst.Op == XCHG && inst.Opcode>>24 == 0x90 {
		if inst.Args[0] == RAX || inst.Args[0] == EAX || inst.Args[0] == AX {
			inst.Op = NOP
			if dataSizeIndex >= 0 {
				inst.Prefix[dataSizeIndex] &^= PrefixImplicit
			}
			inst.Args[0] = nil
			inst.Args[1] = nil
		}
		if repIndex >= 0 && inst.Prefix[repIndex] == 0xF3 {
			inst.Prefix[repIndex] |= PrefixImplicit

	if err != nil {
		return
	}
	inst.GccVersion = strings.TrimSpace(string(stdout))

	return
}

// Return the list of export search paths for this GccgoInstallation.
func (inst *GccgoInstallation) SearchPaths() (paths []string) {
	for _, lpath := range inst.LibPaths {
		spath := filepath.Join(lpath, "go", inst.GccVersion)
		fi, err := os.Stat(spath)
		if err != nil || !fi.IsDir() {
			continue
		}

			if matchArg {
				inst.Out, inst.Arg = inst.Arg, inst.Out
				matchOut, matchArg = matchArg, matchOut
			}
			if matchOut {
				m[pc] = true
				inst.Op = syntax.InstAltMatch
			}

			// build a dispatch operator from the two legs of the alt.
			onePassRunes[pc], inst.Next = mergeRuneSets(
				&onePassRunes[inst.Out], &onePassRunes[inst.Arg], inst.Out, inst.Arg)

// containing the target, if any; otherwise it returns "", 0.
func GoSyntax(inst Inst, pc uint64, symname func(uint64) (string, uint64)) string {
	if symname == nil {
		symname = func(uint64) (string, uint64) { return "", 0 }
	}
	if inst.Op == 0 && inst.Enc == 0 {
		return "WORD $0"
	} else if inst.Op == 0 {
		return "?"
	}
	var args []string
	for i, a := range inst.Args[:] {
		if a == nil {
			break
		}

			case syntax.InstRune, syntax.InstRune1, syntax.InstRuneAny, syntax.InstRuneAnyNotNL:
				// inst.Arg is the match.
				b.push(re, inst.Arg, pos, false)
				pc = inst.Arg
				pos = b.end
				goto CheckAndLoop
			}
			// inst.Out is the match - non-greedy
			b.push(re, inst.Out, b.end, false)
			pc = inst.Out
			goto CheckAndLoop

		case syntax.InstRune:
			r, width := i.step(pos)

      // input of the Dequantize op.
      if (isa<DequantizeOp>(inst)) {
        op = inst;
        value = inst->getOperand(0);
        inst = value.getDefiningOp();
        if (!inst) {
          continue;
        }
        operand = 0;
      }

      ShapedType type;
      float ratio_threshold = kBlockOverRandomSparsityRatio;
      if (isa<ConstOp>(inst)) {
        supported_block_size = sparse_op.GetFloatBlockSize();

	}

	Inst := Unalias(pkg.Scope().Lookup("Inst").Type()).(*Pointer).Elem().(*Named)
	Node := firstFieldType(Inst)
	Tree := firstFieldType(Node)
	if !Identical(Inst, Tree) {
		t.Fatalf("Not a cycle: got %v, want %v", Tree, Inst)
	}
	if Inst != Tree {
		t.Errorf("Duplicate instances in cycle: %s (%p) -> %s (%p) -> %s (%p)", Inst, Inst, Node, Node, Tree, Tree)
	}
}

func GNUSyntax(inst Inst) string {
	var buf bytes.Buffer
	op := inst.Op.String()
	op = saveDot.Replace(op)
	op = strings.Replace(op, ".", "", -1)
	op = strings.Replace(op, "_dot_", ".", -1)
	op = strings.ToLower(op)
	buf.WriteString(op)
	sep := " "
	for i, arg := range inst.Args {
		if arg == nil {
			break
		}
		text := gnuArg(&inst, i, arg)
		if text == "" {
			continue
		}