SelectionDAG.h revision 583bd47f777fe3eb8305872fa0eadab31e833dff 
1//===-- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ---------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file declares the SelectionDAG class, and transitively defines the
11// SDNode class and subclasses.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CODEGEN_SELECTIONDAG_H
16#define LLVM_CODEGEN_SELECTIONDAG_H
17
18#include "llvm/ADT/FoldingSet.h"
19#include "llvm/ADT/ilist"
20#include "llvm/CodeGen/SelectionDAGNodes.h"
21
22#include <list>
23#include <vector>
24#include <map>
25#include <set>
26#include <string>
27
28namespace llvm {
29  class AliasAnalysis;
30  class TargetLowering;
31  class TargetMachine;
32  class MachineDebugInfo;
33  class MachineFunction;
34  class MachineConstantPoolValue;
35  class SDOperand;
36
37/// SelectionDAG class - This is used to represent a portion of an LLVM function
38/// in a low-level Data Dependence DAG representation suitable for instruction
39/// selection.  This DAG is constructed as the first step of instruction
40/// selection in order to allow implementation of machine specific optimizations
41/// and code simplifications.
42///
43/// The representation used by the SelectionDAG is a target-independent
44/// representation, which has some similarities to the GCC RTL representation,
45/// but is significantly more simple, powerful, and is a graph form instead of a
46/// linear form.
47///
48class SelectionDAG {
49  TargetLowering &TLI;
50  MachineFunction &MF;
51  MachineDebugInfo *DI;
52
53  /// Root - The root of the entire DAG.  EntryNode - The starting token.
54  SDOperand Root, EntryNode;
55
56  /// AllNodes - A linked list of nodes in the current DAG.
57  ilist<SDNode> AllNodes;
58
59  /// CSEMap - This structure is used to memoize nodes, automatically performing
60  /// CSE with existing nodes with a duplicate is requested.
61  FoldingSet<SDNode> CSEMap;
62
63public:
64  SelectionDAG(TargetLowering &tli, MachineFunction &mf, MachineDebugInfo *di)
65  : TLI(tli), MF(mf), DI(di) {
66    EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
67  }
68  ~SelectionDAG();
69
70  MachineFunction &getMachineFunction() const { return MF; }
71  const TargetMachine &getTarget() const;
72  TargetLowering &getTargetLoweringInfo() const { return TLI; }
73  MachineDebugInfo *getMachineDebugInfo() const { return DI; }
74
75  /// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
76  ///
77  void viewGraph();
78
79#ifndef NDEBUG
80  std::map<const SDNode *, std::string> NodeGraphAttrs;
81#endif
82
83  /// clearGraphAttrs - Clear all previously defined node graph attributes.
84  /// Intended to be used from a debugging tool (eg. gdb).
85  void clearGraphAttrs();
86
87  /// setGraphAttrs - Set graph attributes for a node. (eg. "color=red".)
88  ///
89  void setGraphAttrs(const SDNode *N, const char *Attrs);
90
91  /// getGraphAttrs - Get graph attributes for a node. (eg. "color=red".)
92  /// Used from getNodeAttributes.
93  const std::string getGraphAttrs(const SDNode *N) const;
94
95  /// setGraphColor - Convenience for setting node color attribute.
96  ///
97  void setGraphColor(const SDNode *N, const char *Color);
98
99  typedef ilist<SDNode>::const_iterator allnodes_const_iterator;
100  allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
101  allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }
102  typedef ilist<SDNode>::iterator allnodes_iterator;
103  allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
104  allnodes_iterator allnodes_end() { return AllNodes.end(); }
105
106  /// getRoot - Return the root tag of the SelectionDAG.
107  ///
108  const SDOperand &getRoot() const { return Root; }
109
110  /// getEntryNode - Return the token chain corresponding to the entry of the
111  /// function.
112  const SDOperand &getEntryNode() const { return EntryNode; }
113
114  /// setRoot - Set the current root tag of the SelectionDAG.
115  ///
116  const SDOperand &setRoot(SDOperand N) { return Root = N; }
117
118  /// Combine - This iterates over the nodes in the SelectionDAG, folding
119  /// certain types of nodes together, or eliminating superfluous nodes.  When
120  /// the AfterLegalize argument is set to 'true', Combine takes care not to
121  /// generate any nodes that will be illegal on the target.
122  void Combine(bool AfterLegalize, AliasAnalysis &AA);
123
124  /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
125  /// compatible with the target instruction selector, as indicated by the
126  /// TargetLowering object.
127  ///
128  /// Note that this is an involved process that may invalidate pointers into
129  /// the graph.
130  void Legalize();
131
132  /// RemoveDeadNodes - This method deletes all unreachable nodes in the
133  /// SelectionDAG.
134  void RemoveDeadNodes();
135
136  /// RemoveDeadNode - Remove the specified node from the system. If any of its
137  /// operands then becomes dead, remove them as well. The vector Deleted is
138  /// populated with nodes that are deleted.
139  void RemoveDeadNode(SDNode *N, std::vector<SDNode*> &Deleted);
140
141  /// DeleteNode - Remove the specified node from the system.  This node must
142  /// have no referrers.
143  void DeleteNode(SDNode *N);
144
145  /// getVTList - Return an SDVTList that represents the list of values
146  /// specified.
147  SDVTList getVTList(MVT::ValueType VT);
148  SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2);
149  SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2,MVT::ValueType VT3);
150  SDVTList getVTList(const MVT::ValueType *VTs, unsigned NumVTs);
151
152  /// getNodeValueTypes - These are obsolete, use getVTList instead.
153  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT) {
154    return getVTList(VT).VTs;
155  }
156  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,
157                                          MVT::ValueType VT2) {
158    return getVTList(VT1, VT2).VTs;
159  }
160  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,MVT::ValueType VT2,
161                                          MVT::ValueType VT3) {
162    return getVTList(VT1, VT2, VT3).VTs;
163  }
164  const MVT::ValueType *getNodeValueTypes(std::vector<MVT::ValueType> &VTList) {
165    return getVTList(&VTList[0], VTList.size()).VTs;
166  }
167
168
169  //===--------------------------------------------------------------------===//
170  // Node creation methods.
171  //
172  SDOperand getString(const std::string &Val);
173  SDOperand getConstant(uint64_t Val, MVT::ValueType VT, bool isTarget = false);
174  SDOperand getTargetConstant(uint64_t Val, MVT::ValueType VT) {
175    return getConstant(Val, VT, true);
176  }
177  SDOperand getConstantFP(double Val, MVT::ValueType VT, bool isTarget = false);
178  SDOperand getTargetConstantFP(double Val, MVT::ValueType VT) {
179    return getConstantFP(Val, VT, true);
180  }
181  SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
182                             int offset = 0, bool isTargetGA = false);
183  SDOperand getTargetGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
184                                   int offset = 0) {
185    return getGlobalAddress(GV, VT, offset, true);
186  }
187  SDOperand getFrameIndex(int FI, MVT::ValueType VT, bool isTarget = false);
188  SDOperand getTargetFrameIndex(int FI, MVT::ValueType VT) {
189    return getFrameIndex(FI, VT, true);
190  }
191  SDOperand getJumpTable(int JTI, MVT::ValueType VT, bool isTarget = false);
192  SDOperand getTargetJumpTable(int JTI, MVT::ValueType VT) {
193    return getJumpTable(JTI, VT, true);
194  }
195  SDOperand getConstantPool(Constant *C, MVT::ValueType VT,
196                            unsigned Align = 0, int Offs = 0, bool isT=false);
197  SDOperand getTargetConstantPool(Constant *C, MVT::ValueType VT,
198                                  unsigned Align = 0, int Offset = 0) {
199    return getConstantPool(C, VT, Align, Offset, true);
200  }
201  SDOperand getConstantPool(MachineConstantPoolValue *C, MVT::ValueType VT,
202                            unsigned Align = 0, int Offs = 0, bool isT=false);
203  SDOperand getTargetConstantPool(MachineConstantPoolValue *C,
204                                  MVT::ValueType VT, unsigned Align = 0,
205                                  int Offset = 0) {
206    return getConstantPool(C, VT, Align, Offset, true);
207  }
208  SDOperand getBasicBlock(MachineBasicBlock *MBB);
209  SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
210  SDOperand getTargetExternalSymbol(const char *Sym, MVT::ValueType VT);
211  SDOperand getValueType(MVT::ValueType);
212  SDOperand getRegister(unsigned Reg, MVT::ValueType VT);
213
214  SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N) {
215    return getNode(ISD::CopyToReg, MVT::Other, Chain,
216                   getRegister(Reg, N.getValueType()), N);
217  }
218
219  // This version of the getCopyToReg method takes an extra operand, which
220  // indicates that there is potentially an incoming flag value (if Flag is not
221  // null) and that there should be a flag result.
222  SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N,
223                         SDOperand Flag) {
224    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
225    SDOperand Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Flag };
226    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
227  }
228
229  // Similar to last getCopyToReg() except parameter Reg is a SDOperand
230  SDOperand getCopyToReg(SDOperand Chain, SDOperand Reg, SDOperand N,
231                         SDOperand Flag) {
232    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
233    SDOperand Ops[] = { Chain, Reg, N, Flag };
234    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
235  }
236
237  SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
238    const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other);
239    SDOperand Ops[] = { Chain, getRegister(Reg, VT) };
240    return getNode(ISD::CopyFromReg, VTs, 2, Ops, 2);
241  }
242
243  // This version of the getCopyFromReg method takes an extra operand, which
244  // indicates that there is potentially an incoming flag value (if Flag is not
245  // null) and that there should be a flag result.
246  SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT,
247                           SDOperand Flag) {
248    const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other, MVT::Flag);
249    SDOperand Ops[] = { Chain, getRegister(Reg, VT), Flag };
250    return getNode(ISD::CopyFromReg, VTs, 3, Ops, Flag.Val ? 3 : 2);
251  }
252
253  SDOperand getCondCode(ISD::CondCode Cond);
254
255  /// getZeroExtendInReg - Return the expression required to zero extend the Op
256  /// value assuming it was the smaller SrcTy value.
257  SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
258
259  /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
260  /// a flag result (to ensure it's not CSE'd).
261  SDOperand getCALLSEQ_START(SDOperand Chain, SDOperand Op) {
262    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
263    SDOperand Ops[] = { Chain,  Op };
264    return getNode(ISD::CALLSEQ_START, VTs, 2, Ops, 2);
265  }
266
267  /// getNode - Gets or creates the specified node.
268  ///
269  SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
270  SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
271  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
272                    SDOperand N1, SDOperand N2);
273  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
274                    SDOperand N1, SDOperand N2, SDOperand N3);
275  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
276                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
277  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
278                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
279                    SDOperand N5);
280  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
281                    const SDOperand *Ops, unsigned NumOps);
282  SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
283                    const SDOperand *Ops, unsigned NumOps);
284  SDOperand getNode(unsigned Opcode, const MVT::ValueType *VTs, unsigned NumVTs,
285                    const SDOperand *Ops, unsigned NumOps);
286  SDOperand getNode(unsigned Opcode, SDVTList VTs,
287                    const SDOperand *Ops, unsigned NumOps);
288
289  /// getSetCC - Helper function to make it easier to build SetCC's if you just
290  /// have an ISD::CondCode instead of an SDOperand.
291  ///
292  SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
293                     ISD::CondCode Cond) {
294    return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
295  }
296
297  /// getSelectCC - Helper function to make it easier to build SelectCC's if you
298  /// just have an ISD::CondCode instead of an SDOperand.
299  ///
300  SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
301                        SDOperand True, SDOperand False, ISD::CondCode Cond) {
302    return getNode(ISD::SELECT_CC, True.getValueType(), LHS, RHS, True, False,
303                   getCondCode(Cond));
304  }
305
306  /// getVAArg - VAArg produces a result and token chain, and takes a pointer
307  /// and a source value as input.
308  SDOperand getVAArg(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
309                     SDOperand SV);
310
311  /// getLoad - Loads are not normal binary operators: their result type is not
312  /// determined by their operands, and they produce a value AND a token chain.
313  ///
314  SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
315                    const Value *SV, int SVOffset, bool isVolatile=false);
316  SDOperand getExtLoad(ISD::LoadExtType ExtType, MVT::ValueType VT,
317                       SDOperand Chain, SDOperand Ptr, const Value *SV,
318                       int SVOffset, MVT::ValueType EVT, bool isVolatile=false);
319  SDOperand getIndexedLoad(SDOperand OrigLoad, SDOperand Base,
320                           SDOperand Offset, ISD::MemOpAddrMode AM);
321  SDOperand getVecLoad(unsigned Count, MVT::ValueType VT, SDOperand Chain,
322                       SDOperand Ptr, SDOperand SV);
323
324  /// getStore - Helper function to build ISD::STORE nodes.
325  ///
326  SDOperand getStore(SDOperand Chain, SDOperand Value, SDOperand Ptr,
327                     const Value *SV, int SVOffset, bool isVolatile=false);
328  SDOperand getTruncStore(SDOperand Chain, SDOperand Value, SDOperand Ptr,
329                          const Value *SV, int SVOffset, MVT::ValueType TVT,
330                          bool isVolatile=false);
331
332  // getSrcValue - construct a node to track a Value* through the backend
333  SDOperand getSrcValue(const Value* I, int offset = 0);
334
335  /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
336  /// specified operands.  If the resultant node already exists in the DAG,
337  /// this does not modify the specified node, instead it returns the node that
338  /// already exists.  If the resultant node does not exist in the DAG, the
339  /// input node is returned.  As a degenerate case, if you specify the same
340  /// input operands as the node already has, the input node is returned.
341  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op);
342  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2);
343  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
344                               SDOperand Op3);
345  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
346                               SDOperand Op3, SDOperand Op4);
347  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
348                               SDOperand Op3, SDOperand Op4, SDOperand Op5);
349  SDOperand UpdateNodeOperands(SDOperand N, SDOperand *Ops, unsigned NumOps);
350
351  /// SelectNodeTo - These are used for target selectors to *mutate* the
352  /// specified node to have the specified return type, Target opcode, and
353  /// operands.  Note that target opcodes are stored as
354  /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field.  The 0th value
355  /// of the resultant node is returned.
356  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
357  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
358                       SDOperand Op1);
359  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
360                       SDOperand Op1, SDOperand Op2);
361  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
362                       SDOperand Op1, SDOperand Op2, SDOperand Op3);
363  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
364                        const SDOperand *Ops, unsigned NumOps);
365  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
366                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
367  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
368                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
369                       SDOperand Op3);
370
371
372  /// getTargetNode - These are used for target selectors to create a new node
373  /// with specified return type(s), target opcode, and operands.
374  ///
375  /// Note that getTargetNode returns the resultant node.  If there is already a
376  /// node of the specified opcode and operands, it returns that node instead of
377  /// the current one.
378  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT);
379  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
380                        SDOperand Op1);
381  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
382                        SDOperand Op1, SDOperand Op2);
383  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
384                        SDOperand Op1, SDOperand Op2, SDOperand Op3);
385  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
386                        const SDOperand *Ops, unsigned NumOps);
387  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
388                        MVT::ValueType VT2, SDOperand Op1);
389  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
390                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
391  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
392                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
393                        SDOperand Op3);
394  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
395                        MVT::ValueType VT2,
396                        const SDOperand *Ops, unsigned NumOps);
397  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
398                        MVT::ValueType VT2, MVT::ValueType VT3,
399                        SDOperand Op1, SDOperand Op2);
400  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
401                        MVT::ValueType VT2, MVT::ValueType VT3,
402                        const SDOperand *Ops, unsigned NumOps);
403
404  /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
405  /// This can cause recursive merging of nodes in the DAG.  Use the first
406  /// version if 'From' is known to have a single result, use the second
407  /// if you have two nodes with identical results, use the third otherwise.
408  ///
409  /// These methods all take an optional vector, which (if not null) is
410  /// populated with any nodes that are deleted from the SelectionDAG, due to
411  /// new equivalences that are discovered.
412  ///
413  void ReplaceAllUsesWith(SDOperand From, SDOperand Op,
414                          std::vector<SDNode*> *Deleted = 0);
415  void ReplaceAllUsesWith(SDNode *From, SDNode *To,
416                          std::vector<SDNode*> *Deleted = 0);
417  void ReplaceAllUsesWith(SDNode *From, const SDOperand *To,
418                          std::vector<SDNode*> *Deleted = 0);
419
420  /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
421  /// uses of other values produced by From.Val alone.  The Deleted vector is
422  /// handled the same was as for ReplaceAllUsesWith, but it is required for
423  /// this method.
424  void ReplaceAllUsesOfValueWith(SDOperand From, SDOperand To,
425                                 std::vector<SDNode*> &Deleted);
426
427  /// AssignNodeIds - Assign a unique node id for each node in the DAG based on
428  /// their allnodes order. It returns the maximum id.
429  unsigned AssignNodeIds();
430
431  /// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
432  /// based on their topological order. It returns the maximum id and a vector
433  /// of the SDNodes* in assigned order by reference.
434  unsigned AssignTopologicalOrder(std::vector<SDNode*> &TopOrder);
435
436  /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
437  /// operation.
438  static bool isCommutativeBinOp(unsigned Opcode) {
439    switch (Opcode) {
440    case ISD::ADD:
441    case ISD::MUL:
442    case ISD::MULHU:
443    case ISD::MULHS:
444    case ISD::FADD:
445    case ISD::FMUL:
446    case ISD::AND:
447    case ISD::OR:
448    case ISD::XOR:
449    case ISD::ADDC:
450    case ISD::ADDE: return true;
451    default: return false;
452    }
453  }
454
455  void dump() const;
456
457  /// FoldSetCC - Constant fold a setcc to true or false.
458  SDOperand FoldSetCC(MVT::ValueType VT, SDOperand N1,
459                      SDOperand N2, ISD::CondCode Cond);
460
461private:
462  void RemoveNodeFromCSEMaps(SDNode *N);
463  SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
464  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op, void *&InsertPos);
465  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op1, SDOperand Op2,
466                               void *&InsertPos);
467  SDNode *FindModifiedNodeSlot(SDNode *N, const SDOperand *Ops, unsigned NumOps,
468                               void *&InsertPos);
469
470  void DeleteNodeNotInCSEMaps(SDNode *N);
471
472  // List of non-single value types.
473  std::list<std::vector<MVT::ValueType> > VTList;
474
475  // Maps to auto-CSE operations.
476  std::vector<CondCodeSDNode*> CondCodeNodes;
477
478  std::vector<SDNode*> ValueTypeNodes;
479  std::map<std::string, SDNode*> ExternalSymbols;
480  std::map<std::string, SDNode*> TargetExternalSymbols;
481  std::map<std::string, StringSDNode*> StringNodes;
482};
483
484template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
485  typedef SelectionDAG::allnodes_iterator nodes_iterator;
486  static nodes_iterator nodes_begin(SelectionDAG *G) {
487    return G->allnodes_begin();
488  }
489  static nodes_iterator nodes_end(SelectionDAG *G) {
490    return G->allnodes_end();
491  }
492};
493
494}  // end namespace llvm
495
496#endif
497