CodeGenInstruction.cpp revision 2a8cd57566dd0eb62831b4c7429e46947a52a879 
1//===- CodeGenInstruction.cpp - CodeGen Instruction Class Wrapper ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the CodeGenInstruction class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenInstruction.h"
15#include "CodeGenTarget.h"
16#include "llvm/TableGen/Error.h"
17#include "llvm/TableGen/Record.h"
18#include "llvm/ADT/StringExtras.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/ADT/STLExtras.h"
21#include <set>
22using namespace llvm;
23
24//===----------------------------------------------------------------------===//
25// CGIOperandList Implementation
26//===----------------------------------------------------------------------===//
27
28CGIOperandList::CGIOperandList(Record *R) : TheDef(R) {
29  isPredicable = false;
30  hasOptionalDef = false;
31  isVariadic = false;
32
33  DagInit *OutDI = R->getValueAsDag("OutOperandList");
34
35  if (DefInit *Init = dynamic_cast<DefInit*>(OutDI->getOperator())) {
36    if (Init->getDef()->getName() != "outs")
37      throw R->getName() + ": invalid def name for output list: use 'outs'";
38  } else
39    throw R->getName() + ": invalid output list: use 'outs'";
40
41  NumDefs = OutDI->getNumArgs();
42
43  DagInit *InDI = R->getValueAsDag("InOperandList");
44  if (DefInit *Init = dynamic_cast<DefInit*>(InDI->getOperator())) {
45    if (Init->getDef()->getName() != "ins")
46      throw R->getName() + ": invalid def name for input list: use 'ins'";
47  } else
48    throw R->getName() + ": invalid input list: use 'ins'";
49
50  unsigned MIOperandNo = 0;
51  std::set<std::string> OperandNames;
52  for (unsigned i = 0, e = InDI->getNumArgs()+OutDI->getNumArgs(); i != e; ++i){
53    Init *ArgInit;
54    std::string ArgName;
55    if (i < NumDefs) {
56      ArgInit = OutDI->getArg(i);
57      ArgName = OutDI->getArgName(i);
58    } else {
59      ArgInit = InDI->getArg(i-NumDefs);
60      ArgName = InDI->getArgName(i-NumDefs);
61    }
62
63    DefInit *Arg = dynamic_cast<DefInit*>(ArgInit);
64    if (!Arg)
65      throw "Illegal operand for the '" + R->getName() + "' instruction!";
66
67    Record *Rec = Arg->getDef();
68    std::string PrintMethod = "printOperand";
69    std::string EncoderMethod;
70    std::string OperandType = "OPERAND_UNKNOWN";
71    unsigned NumOps = 1;
72    DagInit *MIOpInfo = 0;
73    if (Rec->isSubClassOf("RegisterOperand")) {
74      PrintMethod = Rec->getValueAsString("PrintMethod");
75    } else if (Rec->isSubClassOf("Operand")) {
76      PrintMethod = Rec->getValueAsString("PrintMethod");
77      OperandType = Rec->getValueAsString("OperandType");
78      // If there is an explicit encoder method, use it.
79      EncoderMethod = Rec->getValueAsString("EncoderMethod");
80      MIOpInfo = Rec->getValueAsDag("MIOperandInfo");
81
82      // Verify that MIOpInfo has an 'ops' root value.
83      if (!dynamic_cast<DefInit*>(MIOpInfo->getOperator()) ||
84          dynamic_cast<DefInit*>(MIOpInfo->getOperator())
85          ->getDef()->getName() != "ops")
86        throw "Bad value for MIOperandInfo in operand '" + Rec->getName() +
87        "'\n";
88
89      // If we have MIOpInfo, then we have #operands equal to number of entries
90      // in MIOperandInfo.
91      if (unsigned NumArgs = MIOpInfo->getNumArgs())
92        NumOps = NumArgs;
93
94      if (Rec->isSubClassOf("PredicateOperand"))
95        isPredicable = true;
96      else if (Rec->isSubClassOf("OptionalDefOperand"))
97        hasOptionalDef = true;
98    } else if (Rec->getName() == "variable_ops") {
99      isVariadic = true;
100      continue;
101    } else if (Rec->isSubClassOf("RegisterClass")) {
102      OperandType = "OPERAND_REGISTER";
103    } else if (!Rec->isSubClassOf("PointerLikeRegClass") &&
104               Rec->getName() != "unknown")
105      throw "Unknown operand class '" + Rec->getName() +
106      "' in '" + R->getName() + "' instruction!";
107
108    // Check that the operand has a name and that it's unique.
109    if (ArgName.empty())
110      throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
111      " has no name!";
112    if (!OperandNames.insert(ArgName).second)
113      throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
114      " has the same name as a previous operand!";
115
116    OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod, EncoderMethod,
117                                      OperandType, MIOperandNo, NumOps,
118                                      MIOpInfo));
119    MIOperandNo += NumOps;
120  }
121
122
123  // Make sure the constraints list for each operand is large enough to hold
124  // constraint info, even if none is present.
125  for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
126    OperandList[i].Constraints.resize(OperandList[i].MINumOperands);
127}
128
129
130/// getOperandNamed - Return the index of the operand with the specified
131/// non-empty name.  If the instruction does not have an operand with the
132/// specified name, throw an exception.
133///
134unsigned CGIOperandList::getOperandNamed(StringRef Name) const {
135  unsigned OpIdx;
136  if (hasOperandNamed(Name, OpIdx)) return OpIdx;
137  throw "'" + TheDef->getName() + "' does not have an operand named '$" +
138    Name.str() + "'!";
139}
140
141/// hasOperandNamed - Query whether the instruction has an operand of the
142/// given name. If so, return true and set OpIdx to the index of the
143/// operand. Otherwise, return false.
144bool CGIOperandList::hasOperandNamed(StringRef Name, unsigned &OpIdx) const {
145  assert(!Name.empty() && "Cannot search for operand with no name!");
146  for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
147    if (OperandList[i].Name == Name) {
148      OpIdx = i;
149      return true;
150    }
151  return false;
152}
153
154std::pair<unsigned,unsigned>
155CGIOperandList::ParseOperandName(const std::string &Op, bool AllowWholeOp) {
156  if (Op.empty() || Op[0] != '$')
157    throw TheDef->getName() + ": Illegal operand name: '" + Op + "'";
158
159  std::string OpName = Op.substr(1);
160  std::string SubOpName;
161
162  // Check to see if this is $foo.bar.
163  std::string::size_type DotIdx = OpName.find_first_of(".");
164  if (DotIdx != std::string::npos) {
165    SubOpName = OpName.substr(DotIdx+1);
166    if (SubOpName.empty())
167      throw TheDef->getName() + ": illegal empty suboperand name in '" +Op +"'";
168    OpName = OpName.substr(0, DotIdx);
169  }
170
171  unsigned OpIdx = getOperandNamed(OpName);
172
173  if (SubOpName.empty()) {  // If no suboperand name was specified:
174    // If one was needed, throw.
175    if (OperandList[OpIdx].MINumOperands > 1 && !AllowWholeOp &&
176        SubOpName.empty())
177      throw TheDef->getName() + ": Illegal to refer to"
178      " whole operand part of complex operand '" + Op + "'";
179
180    // Otherwise, return the operand.
181    return std::make_pair(OpIdx, 0U);
182  }
183
184  // Find the suboperand number involved.
185  DagInit *MIOpInfo = OperandList[OpIdx].MIOperandInfo;
186  if (MIOpInfo == 0)
187    throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";
188
189  // Find the operand with the right name.
190  for (unsigned i = 0, e = MIOpInfo->getNumArgs(); i != e; ++i)
191    if (MIOpInfo->getArgName(i) == SubOpName)
192      return std::make_pair(OpIdx, i);
193
194  // Otherwise, didn't find it!
195  throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";
196}
197
198static void ParseConstraint(const std::string &CStr, CGIOperandList &Ops) {
199  // EARLY_CLOBBER: @early $reg
200  std::string::size_type wpos = CStr.find_first_of(" \t");
201  std::string::size_type start = CStr.find_first_not_of(" \t");
202  std::string Tok = CStr.substr(start, wpos - start);
203  if (Tok == "@earlyclobber") {
204    std::string Name = CStr.substr(wpos+1);
205    wpos = Name.find_first_not_of(" \t");
206    if (wpos == std::string::npos)
207      throw "Illegal format for @earlyclobber constraint: '" + CStr + "'";
208    Name = Name.substr(wpos);
209    std::pair<unsigned,unsigned> Op = Ops.ParseOperandName(Name, false);
210
211    // Build the string for the operand
212    if (!Ops[Op.first].Constraints[Op.second].isNone())
213      throw "Operand '" + Name + "' cannot have multiple constraints!";
214    Ops[Op.first].Constraints[Op.second] =
215    CGIOperandList::ConstraintInfo::getEarlyClobber();
216    return;
217  }
218
219  // Only other constraint is "TIED_TO" for now.
220  std::string::size_type pos = CStr.find_first_of('=');
221  assert(pos != std::string::npos && "Unrecognized constraint");
222  start = CStr.find_first_not_of(" \t");
223  std::string Name = CStr.substr(start, pos - start);
224
225  // TIED_TO: $src1 = $dst
226  wpos = Name.find_first_of(" \t");
227  if (wpos == std::string::npos)
228    throw "Illegal format for tied-to constraint: '" + CStr + "'";
229  std::string DestOpName = Name.substr(0, wpos);
230  std::pair<unsigned,unsigned> DestOp = Ops.ParseOperandName(DestOpName, false);
231
232  Name = CStr.substr(pos+1);
233  wpos = Name.find_first_not_of(" \t");
234  if (wpos == std::string::npos)
235    throw "Illegal format for tied-to constraint: '" + CStr + "'";
236
237  std::pair<unsigned,unsigned> SrcOp =
238  Ops.ParseOperandName(Name.substr(wpos), false);
239  if (SrcOp > DestOp)
240    throw "Illegal tied-to operand constraint '" + CStr + "'";
241
242
243  unsigned FlatOpNo = Ops.getFlattenedOperandNumber(SrcOp);
244
245  if (!Ops[DestOp.first].Constraints[DestOp.second].isNone())
246    throw "Operand '" + DestOpName + "' cannot have multiple constraints!";
247  Ops[DestOp.first].Constraints[DestOp.second] =
248    CGIOperandList::ConstraintInfo::getTied(FlatOpNo);
249}
250
251static void ParseConstraints(const std::string &CStr, CGIOperandList &Ops) {
252  if (CStr.empty()) return;
253
254  const std::string delims(",");
255  std::string::size_type bidx, eidx;
256
257  bidx = CStr.find_first_not_of(delims);
258  while (bidx != std::string::npos) {
259    eidx = CStr.find_first_of(delims, bidx);
260    if (eidx == std::string::npos)
261      eidx = CStr.length();
262
263    ParseConstraint(CStr.substr(bidx, eidx - bidx), Ops);
264    bidx = CStr.find_first_not_of(delims, eidx);
265  }
266}
267
268void CGIOperandList::ProcessDisableEncoding(std::string DisableEncoding) {
269  while (1) {
270    std::pair<StringRef, StringRef> P = getToken(DisableEncoding, " ,\t");
271    std::string OpName = P.first;
272    DisableEncoding = P.second;
273    if (OpName.empty()) break;
274
275    // Figure out which operand this is.
276    std::pair<unsigned,unsigned> Op = ParseOperandName(OpName, false);
277
278    // Mark the operand as not-to-be encoded.
279    if (Op.second >= OperandList[Op.first].DoNotEncode.size())
280      OperandList[Op.first].DoNotEncode.resize(Op.second+1);
281    OperandList[Op.first].DoNotEncode[Op.second] = true;
282  }
283
284}
285
286//===----------------------------------------------------------------------===//
287// CodeGenInstruction Implementation
288//===----------------------------------------------------------------------===//
289
290CodeGenInstruction::CodeGenInstruction(Record *R) : TheDef(R), Operands(R) {
291  Namespace = R->getValueAsString("Namespace");
292  AsmString = R->getValueAsString("AsmString");
293
294  isReturn     = R->getValueAsBit("isReturn");
295  isBranch     = R->getValueAsBit("isBranch");
296  isIndirectBranch = R->getValueAsBit("isIndirectBranch");
297  isCompare    = R->getValueAsBit("isCompare");
298  isMoveImm    = R->getValueAsBit("isMoveImm");
299  isBitcast    = R->getValueAsBit("isBitcast");
300  isBarrier    = R->getValueAsBit("isBarrier");
301  isCall       = R->getValueAsBit("isCall");
302  canFoldAsLoad = R->getValueAsBit("canFoldAsLoad");
303  mayLoad      = R->getValueAsBit("mayLoad");
304  mayStore     = R->getValueAsBit("mayStore");
305  isPredicable = Operands.isPredicable || R->getValueAsBit("isPredicable");
306  isConvertibleToThreeAddress = R->getValueAsBit("isConvertibleToThreeAddress");
307  isCommutable = R->getValueAsBit("isCommutable");
308  isTerminator = R->getValueAsBit("isTerminator");
309  isReMaterializable = R->getValueAsBit("isReMaterializable");
310  hasDelaySlot = R->getValueAsBit("hasDelaySlot");
311  usesCustomInserter = R->getValueAsBit("usesCustomInserter");
312  hasPostISelHook = R->getValueAsBit("hasPostISelHook");
313  hasCtrlDep   = R->getValueAsBit("hasCtrlDep");
314  isNotDuplicable = R->getValueAsBit("isNotDuplicable");
315  hasSideEffects = R->getValueAsBit("hasSideEffects");
316  neverHasSideEffects = R->getValueAsBit("neverHasSideEffects");
317  isAsCheapAsAMove = R->getValueAsBit("isAsCheapAsAMove");
318  hasExtraSrcRegAllocReq = R->getValueAsBit("hasExtraSrcRegAllocReq");
319  hasExtraDefRegAllocReq = R->getValueAsBit("hasExtraDefRegAllocReq");
320  isCodeGenOnly = R->getValueAsBit("isCodeGenOnly");
321  isPseudo = R->getValueAsBit("isPseudo");
322  ImplicitDefs = R->getValueAsListOfDefs("Defs");
323  ImplicitUses = R->getValueAsListOfDefs("Uses");
324
325  if (neverHasSideEffects + hasSideEffects > 1)
326    throw R->getName() + ": multiple conflicting side-effect flags set!";
327
328  // Parse Constraints.
329  ParseConstraints(R->getValueAsString("Constraints"), Operands);
330
331  // Parse the DisableEncoding field.
332  Operands.ProcessDisableEncoding(R->getValueAsString("DisableEncoding"));
333}
334
335/// HasOneImplicitDefWithKnownVT - If the instruction has at least one
336/// implicit def and it has a known VT, return the VT, otherwise return
337/// MVT::Other.
338MVT::SimpleValueType CodeGenInstruction::
339HasOneImplicitDefWithKnownVT(const CodeGenTarget &TargetInfo) const {
340  if (ImplicitDefs.empty()) return MVT::Other;
341
342  // Check to see if the first implicit def has a resolvable type.
343  Record *FirstImplicitDef = ImplicitDefs[0];
344  assert(FirstImplicitDef->isSubClassOf("Register"));
345  const std::vector<MVT::SimpleValueType> &RegVTs =
346    TargetInfo.getRegisterVTs(FirstImplicitDef);
347  if (RegVTs.size() == 1)
348    return RegVTs[0];
349  return MVT::Other;
350}
351
352
353/// FlattenAsmStringVariants - Flatten the specified AsmString to only
354/// include text from the specified variant, returning the new string.
355std::string CodeGenInstruction::
356FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
357  std::string Res = "";
358
359  for (;;) {
360    // Find the start of the next variant string.
361    size_t VariantsStart = 0;
362    for (size_t e = Cur.size(); VariantsStart != e; ++VariantsStart)
363      if (Cur[VariantsStart] == '{' &&
364          (VariantsStart == 0 || (Cur[VariantsStart-1] != '$' &&
365                                  Cur[VariantsStart-1] != '\\')))
366        break;
367
368    // Add the prefix to the result.
369    Res += Cur.slice(0, VariantsStart);
370    if (VariantsStart == Cur.size())
371      break;
372
373    ++VariantsStart; // Skip the '{'.
374
375    // Scan to the end of the variants string.
376    size_t VariantsEnd = VariantsStart;
377    unsigned NestedBraces = 1;
378    for (size_t e = Cur.size(); VariantsEnd != e; ++VariantsEnd) {
379      if (Cur[VariantsEnd] == '}' && Cur[VariantsEnd-1] != '\\') {
380        if (--NestedBraces == 0)
381          break;
382      } else if (Cur[VariantsEnd] == '{')
383        ++NestedBraces;
384    }
385
386    // Select the Nth variant (or empty).
387    StringRef Selection = Cur.slice(VariantsStart, VariantsEnd);
388    for (unsigned i = 0; i != Variant; ++i)
389      Selection = Selection.split('|').second;
390    Res += Selection.split('|').first;
391
392    assert(VariantsEnd != Cur.size() &&
393           "Unterminated variants in assembly string!");
394    Cur = Cur.substr(VariantsEnd + 1);
395  }
396
397  return Res;
398}
399
400
401//===----------------------------------------------------------------------===//
402/// CodeGenInstAlias Implementation
403//===----------------------------------------------------------------------===//
404
405/// tryAliasOpMatch - This is a helper function for the CodeGenInstAlias
406/// constructor.  It checks if an argument in an InstAlias pattern matches
407/// the corresponding operand of the instruction.  It returns true on a
408/// successful match, with ResOp set to the result operand to be used.
409bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
410                                       Record *InstOpRec, bool hasSubOps,
411                                       SMLoc Loc, CodeGenTarget &T,
412                                       ResultOperand &ResOp) {
413  Init *Arg = Result->getArg(AliasOpNo);
414  DefInit *ADI = dynamic_cast<DefInit*>(Arg);
415
416  if (ADI && ADI->getDef() == InstOpRec) {
417    // If the operand is a record, it must have a name, and the record type
418    // must match up with the instruction's argument type.
419    if (Result->getArgName(AliasOpNo).empty())
420      throw TGError(Loc, "result argument #" + utostr(AliasOpNo) +
421                    " must have a name!");
422    ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
423    return true;
424  }
425
426  // For register operands, the source register class can be a subclass
427  // of the instruction register class, not just an exact match.
428  if (ADI && ADI->getDef()->isSubClassOf("RegisterClass")) {
429    if (!InstOpRec->isSubClassOf("RegisterClass"))
430      return false;
431    if (!T.getRegisterClass(InstOpRec)
432              .hasSubClass(&T.getRegisterClass(ADI->getDef())))
433      return false;
434    ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
435    return true;
436  }
437
438  // Handle explicit registers.
439  if (ADI && ADI->getDef()->isSubClassOf("Register")) {
440    if (InstOpRec->isSubClassOf("OptionalDefOperand")) {
441      DagInit *DI = InstOpRec->getValueAsDag("MIOperandInfo");
442      // The operand info should only have a single (register) entry. We
443      // want the register class of it.
444      InstOpRec = dynamic_cast<DefInit*>(DI->getArg(0))->getDef();
445    }
446
447    if (InstOpRec->isSubClassOf("RegisterOperand"))
448      InstOpRec = InstOpRec->getValueAsDef("RegClass");
449
450    if (!InstOpRec->isSubClassOf("RegisterClass"))
451      return false;
452
453    if (!T.getRegisterClass(InstOpRec)
454        .contains(T.getRegBank().getReg(ADI->getDef())))
455      throw TGError(Loc, "fixed register " + ADI->getDef()->getName() +
456                    " is not a member of the " + InstOpRec->getName() +
457                    " register class!");
458
459    if (!Result->getArgName(AliasOpNo).empty())
460      throw TGError(Loc, "result fixed register argument must "
461                    "not have a name!");
462
463    ResOp = ResultOperand(ADI->getDef());
464    return true;
465  }
466
467  // Handle "zero_reg" for optional def operands.
468  if (ADI && ADI->getDef()->getName() == "zero_reg") {
469
470    // Check if this is an optional def.
471    if (!InstOpRec->isSubClassOf("OptionalDefOperand"))
472      throw TGError(Loc, "reg0 used for result that is not an "
473                    "OptionalDefOperand!");
474
475    ResOp = ResultOperand(static_cast<Record*>(0));
476    return true;
477  }
478
479  // Literal integers.
480  if (IntInit *II = dynamic_cast<IntInit*>(Arg)) {
481    if (hasSubOps || !InstOpRec->isSubClassOf("Operand"))
482      return false;
483    // Integer arguments can't have names.
484    if (!Result->getArgName(AliasOpNo).empty())
485      throw TGError(Loc, "result argument #" + utostr(AliasOpNo) +
486                    " must not have a name!");
487    ResOp = ResultOperand(II->getValue());
488    return true;
489  }
490
491  // If both are Operands with the same MVT, allow the conversion. It's
492  // up to the user to make sure the values are appropriate, just like
493  // for isel Pat's.
494  if (InstOpRec->isSubClassOf("Operand") &&
495      ADI->getDef()->isSubClassOf("Operand")) {
496    // FIXME: What other attributes should we check here? Identical
497    // MIOperandInfo perhaps?
498    if (InstOpRec->getValueInit("Type") != ADI->getDef()->getValueInit("Type"))
499      return false;
500    ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
501    return true;
502  }
503
504  return false;
505}
506
507CodeGenInstAlias::CodeGenInstAlias(Record *R, CodeGenTarget &T) : TheDef(R) {
508  AsmString = R->getValueAsString("AsmString");
509  Result = R->getValueAsDag("ResultInst");
510
511  // Verify that the root of the result is an instruction.
512  DefInit *DI = dynamic_cast<DefInit*>(Result->getOperator());
513  if (DI == 0 || !DI->getDef()->isSubClassOf("Instruction"))
514    throw TGError(R->getLoc(), "result of inst alias should be an instruction");
515
516  ResultInst = &T.getInstruction(DI->getDef());
517
518  // NameClass - If argument names are repeated, we need to verify they have
519  // the same class.
520  StringMap<Record*> NameClass;
521  for (unsigned i = 0, e = Result->getNumArgs(); i != e; ++i) {
522    DefInit *ADI = dynamic_cast<DefInit*>(Result->getArg(i));
523    if (!ADI || Result->getArgName(i).empty())
524      continue;
525    // Verify we don't have something like: (someinst GR16:$foo, GR32:$foo)
526    // $foo can exist multiple times in the result list, but it must have the
527    // same type.
528    Record *&Entry = NameClass[Result->getArgName(i)];
529    if (Entry && Entry != ADI->getDef())
530      throw TGError(R->getLoc(), "result value $" + Result->getArgName(i) +
531                    " is both " + Entry->getName() + " and " +
532                    ADI->getDef()->getName() + "!");
533    Entry = ADI->getDef();
534  }
535
536  // Decode and validate the arguments of the result.
537  unsigned AliasOpNo = 0;
538  for (unsigned i = 0, e = ResultInst->Operands.size(); i != e; ++i) {
539
540    // Tied registers don't have an entry in the result dag.
541    if (ResultInst->Operands[i].getTiedRegister() != -1)
542      continue;
543
544    if (AliasOpNo >= Result->getNumArgs())
545      throw TGError(R->getLoc(), "not enough arguments for instruction!");
546
547    Record *InstOpRec = ResultInst->Operands[i].Rec;
548    unsigned NumSubOps = ResultInst->Operands[i].MINumOperands;
549    ResultOperand ResOp(static_cast<int64_t>(0));
550    if (tryAliasOpMatch(Result, AliasOpNo, InstOpRec, (NumSubOps > 1),
551                        R->getLoc(), T, ResOp)) {
552      ResultOperands.push_back(ResOp);
553      ResultInstOperandIndex.push_back(std::make_pair(i, -1));
554      ++AliasOpNo;
555      continue;
556    }
557
558    // If the argument did not match the instruction operand, and the operand
559    // is composed of multiple suboperands, try matching the suboperands.
560    if (NumSubOps > 1) {
561      DagInit *MIOI = ResultInst->Operands[i].MIOperandInfo;
562      for (unsigned SubOp = 0; SubOp != NumSubOps; ++SubOp) {
563        if (AliasOpNo >= Result->getNumArgs())
564          throw TGError(R->getLoc(), "not enough arguments for instruction!");
565        Record *SubRec = dynamic_cast<DefInit*>(MIOI->getArg(SubOp))->getDef();
566        if (tryAliasOpMatch(Result, AliasOpNo, SubRec, false,
567                            R->getLoc(), T, ResOp)) {
568          ResultOperands.push_back(ResOp);
569          ResultInstOperandIndex.push_back(std::make_pair(i, SubOp));
570          ++AliasOpNo;
571        } else {
572          throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
573                        " does not match instruction operand class " +
574                        (SubOp == 0 ? InstOpRec->getName() :SubRec->getName()));
575        }
576      }
577      continue;
578    }
579    throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
580                  " does not match instruction operand class " +
581                  InstOpRec->getName());
582  }
583
584  if (AliasOpNo != Result->getNumArgs())
585    throw TGError(R->getLoc(), "too many operands for instruction!");
586}
587