SelectionDAG.h revision 66978ee97773aa76c3f15bee2fc77e5905aaf068 
1//===-- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ---------*- C++ -*-===//
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 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/ilist.h"
19#include "llvm/ADT/DenseSet.h"
20#include "llvm/ADT/FoldingSet.h"
21#include "llvm/ADT/StringMap.h"
22#include "llvm/CodeGen/SelectionDAGNodes.h"
23
24#include <cassert>
25#include <vector>
26#include <map>
27#include <string>
28
29namespace llvm {
30
31class AliasAnalysis;
32class TargetLowering;
33class TargetMachine;
34class MachineModuleInfo;
35class DwarfWriter;
36class MachineFunction;
37class MachineConstantPoolValue;
38class FunctionLoweringInfo;
39
40template<> struct ilist_traits<SDNode> : public ilist_default_traits<SDNode> {
41private:
42  mutable SDNode Sentinel;
43public:
44  ilist_traits() : Sentinel(ISD::DELETED_NODE, SDVTList()) {}
45
46  SDNode *createSentinel() const {
47    return &Sentinel;
48  }
49  static void destroySentinel(SDNode *) {}
50
51  static void deleteNode(SDNode *) {
52    assert(0 && "ilist_traits<SDNode> shouldn't see a deleteNode call!");
53  }
54private:
55  static void createNode(const SDNode &);
56};
57
58enum CombineLevel {
59  Unrestricted,   // Combine may create illegal operations and illegal types.
60  NoIllegalTypes, // Combine may create illegal operations but no illegal types.
61  NoIllegalOperations // Combine may only create legal operations and types.
62};
63
64/// SelectionDAG class - This is used to represent a portion of an LLVM function
65/// in a low-level Data Dependence DAG representation suitable for instruction
66/// selection.  This DAG is constructed as the first step of instruction
67/// selection in order to allow implementation of machine specific optimizations
68/// and code simplifications.
69///
70/// The representation used by the SelectionDAG is a target-independent
71/// representation, which has some similarities to the GCC RTL representation,
72/// but is significantly more simple, powerful, and is a graph form instead of a
73/// linear form.
74///
75class SelectionDAG {
76  TargetLowering &TLI;
77  MachineFunction *MF;
78  FunctionLoweringInfo &FLI;
79  MachineModuleInfo *MMI;
80  DwarfWriter *DW;
81
82  /// EntryNode - The starting token.
83  SDNode EntryNode;
84
85  /// Root - The root of the entire DAG.
86  SDValue Root;
87
88  /// AllNodes - A linked list of nodes in the current DAG.
89  ilist<SDNode> AllNodes;
90
91  /// NodeAllocatorType - The AllocatorType for allocating SDNodes. We use
92  /// pool allocation with recycling.
93  typedef RecyclingAllocator<BumpPtrAllocator, SDNode, sizeof(LargestSDNode),
94                             AlignOf<MostAlignedSDNode>::Alignment>
95    NodeAllocatorType;
96
97  /// NodeAllocator - Pool allocation for nodes.
98  NodeAllocatorType NodeAllocator;
99
100  /// CSEMap - This structure is used to memoize nodes, automatically performing
101  /// CSE with existing nodes with a duplicate is requested.
102  FoldingSet<SDNode> CSEMap;
103
104  /// OperandAllocator - Pool allocation for machine-opcode SDNode operands.
105  BumpPtrAllocator OperandAllocator;
106
107  /// Allocator - Pool allocation for misc. objects that are created once per
108  /// SelectionDAG.
109  BumpPtrAllocator Allocator;
110
111  /// VerifyNode - Sanity check the given node.  Aborts if it is invalid.
112  void VerifyNode(SDNode *N);
113
114  /// setGraphColorHelper - Implementation of setSubgraphColor.
115  /// Return whether we had to truncate the search.
116  ///
117  bool setSubgraphColorHelper(SDNode *N, const char *Color, DenseSet<SDNode *> &visited,
118                              int level, bool &printed);
119
120public:
121  SelectionDAG(TargetLowering &tli, FunctionLoweringInfo &fli);
122  ~SelectionDAG();
123
124  /// init - Prepare this SelectionDAG to process code in the given
125  /// MachineFunction.
126  ///
127  void init(MachineFunction &mf, MachineModuleInfo *mmi, DwarfWriter *dw);
128
129  /// clear - Clear state and free memory necessary to make this
130  /// SelectionDAG ready to process a new block.
131  ///
132  void clear();
133
134  MachineFunction &getMachineFunction() const { return *MF; }
135  const TargetMachine &getTarget() const;
136  TargetLowering &getTargetLoweringInfo() const { return TLI; }
137  FunctionLoweringInfo &getFunctionLoweringInfo() const { return FLI; }
138  MachineModuleInfo *getMachineModuleInfo() const { return MMI; }
139  DwarfWriter *getDwarfWriter() const { return DW; }
140
141  /// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
142  ///
143  void viewGraph(const std::string &Title);
144  void viewGraph();
145
146#ifndef NDEBUG
147  std::map<const SDNode *, std::string> NodeGraphAttrs;
148#endif
149
150  /// clearGraphAttrs - Clear all previously defined node graph attributes.
151  /// Intended to be used from a debugging tool (eg. gdb).
152  void clearGraphAttrs();
153
154  /// setGraphAttrs - Set graph attributes for a node. (eg. "color=red".)
155  ///
156  void setGraphAttrs(const SDNode *N, const char *Attrs);
157
158  /// getGraphAttrs - Get graph attributes for a node. (eg. "color=red".)
159  /// Used from getNodeAttributes.
160  const std::string getGraphAttrs(const SDNode *N) const;
161
162  /// setGraphColor - Convenience for setting node color attribute.
163  ///
164  void setGraphColor(const SDNode *N, const char *Color);
165
166  /// setGraphColor - Convenience for setting subgraph color attribute.
167  ///
168  void setSubgraphColor(SDNode *N, const char *Color);
169
170  typedef ilist<SDNode>::const_iterator allnodes_const_iterator;
171  allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
172  allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }
173  typedef ilist<SDNode>::iterator allnodes_iterator;
174  allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
175  allnodes_iterator allnodes_end() { return AllNodes.end(); }
176  ilist<SDNode>::size_type allnodes_size() const {
177    return AllNodes.size();
178  }
179
180  /// getRoot - Return the root tag of the SelectionDAG.
181  ///
182  const SDValue &getRoot() const { return Root; }
183
184  /// getEntryNode - Return the token chain corresponding to the entry of the
185  /// function.
186  SDValue getEntryNode() const {
187    return SDValue(const_cast<SDNode *>(&EntryNode), 0);
188  }
189
190  /// setRoot - Set the current root tag of the SelectionDAG.
191  ///
192  const SDValue &setRoot(SDValue N) {
193    assert((!N.getNode() || N.getValueType() == MVT::Other) &&
194           "DAG root value is not a chain!");
195    return Root = N;
196  }
197
198  /// Combine - This iterates over the nodes in the SelectionDAG, folding
199  /// certain types of nodes together, or eliminating superfluous nodes.  The
200  /// Level argument controls whether Combine is allowed to produce nodes and
201  /// types that are illegal on the target.
202  void Combine(CombineLevel Level, AliasAnalysis &AA, bool Fast);
203
204  /// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that
205  /// only uses types natively supported by the target.  Returns "true" if it
206  /// made any changes.
207  ///
208  /// Note that this is an involved process that may invalidate pointers into
209  /// the graph.
210  bool LegalizeTypes();
211
212  /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
213  /// compatible with the target instruction selector, as indicated by the
214  /// TargetLowering object.
215  ///
216  /// Note that this is an involved process that may invalidate pointers into
217  /// the graph.
218  void Legalize(bool TypesNeedLegalizing);
219
220  /// RemoveDeadNodes - This method deletes all unreachable nodes in the
221  /// SelectionDAG.
222  void RemoveDeadNodes();
223
224  /// DeleteNode - Remove the specified node from the system.  This node must
225  /// have no referrers.
226  void DeleteNode(SDNode *N);
227
228  /// getVTList - Return an SDVTList that represents the list of values
229  /// specified.
230  SDVTList getVTList(MVT VT);
231  SDVTList getVTList(MVT VT1, MVT VT2);
232  SDVTList getVTList(MVT VT1, MVT VT2, MVT VT3);
233  SDVTList getVTList(MVT VT1, MVT VT2, MVT VT3, MVT VT4);
234  SDVTList getVTList(const MVT *VTs, unsigned NumVTs);
235
236  /// getNodeValueTypes - These are obsolete, use getVTList instead.
237  const MVT *getNodeValueTypes(MVT VT) {
238    return getVTList(VT).VTs;
239  }
240  const MVT *getNodeValueTypes(MVT VT1, MVT VT2) {
241    return getVTList(VT1, VT2).VTs;
242  }
243  const MVT *getNodeValueTypes(MVT VT1, MVT VT2, MVT VT3) {
244    return getVTList(VT1, VT2, VT3).VTs;
245  }
246  const MVT *getNodeValueTypes(MVT VT1, MVT VT2, MVT VT3, MVT VT4) {
247    return getVTList(VT1, VT2, VT3, VT4).VTs;
248  }
249  const MVT *getNodeValueTypes(const std::vector<MVT> &vtList) {
250    return getVTList(&vtList[0], (unsigned)vtList.size()).VTs;
251  }
252
253
254  //===--------------------------------------------------------------------===//
255  // Node creation methods.
256  //
257  SDValue getConstant(uint64_t Val, MVT VT, bool isTarget = false);
258  SDValue getConstant(const APInt &Val, MVT VT, bool isTarget = false);
259  SDValue getConstant(const ConstantInt &Val, MVT VT, bool isTarget = false);
260  SDValue getIntPtrConstant(uint64_t Val, bool isTarget = false);
261  SDValue getTargetConstant(uint64_t Val, MVT VT) {
262    return getConstant(Val, VT, true);
263  }
264  SDValue getTargetConstant(const APInt &Val, MVT VT) {
265    return getConstant(Val, VT, true);
266  }
267  SDValue getTargetConstant(const ConstantInt &Val, MVT VT) {
268    return getConstant(Val, VT, true);
269  }
270  SDValue getConstantFP(double Val, MVT VT, bool isTarget = false);
271  SDValue getConstantFP(const APFloat& Val, MVT VT, bool isTarget = false);
272  SDValue getConstantFP(const ConstantFP &CF, MVT VT, bool isTarget = false);
273  SDValue getTargetConstantFP(double Val, MVT VT) {
274    return getConstantFP(Val, VT, true);
275  }
276  SDValue getTargetConstantFP(const APFloat& Val, MVT VT) {
277    return getConstantFP(Val, VT, true);
278  }
279  SDValue getTargetConstantFP(const ConstantFP &Val, MVT VT) {
280    return getConstantFP(Val, VT, true);
281  }
282  SDValue getGlobalAddress(const GlobalValue *GV, MVT VT,
283                           int64_t offset = 0, bool isTargetGA = false);
284  SDValue getTargetGlobalAddress(const GlobalValue *GV, MVT VT,
285                                 int64_t offset = 0) {
286    return getGlobalAddress(GV, VT, offset, true);
287  }
288  SDValue getFrameIndex(int FI, MVT VT, bool isTarget = false);
289  SDValue getTargetFrameIndex(int FI, MVT VT) {
290    return getFrameIndex(FI, VT, true);
291  }
292  SDValue getJumpTable(int JTI, MVT VT, bool isTarget = false);
293  SDValue getTargetJumpTable(int JTI, MVT VT) {
294    return getJumpTable(JTI, VT, true);
295  }
296  SDValue getConstantPool(Constant *C, MVT VT,
297                            unsigned Align = 0, int Offs = 0, bool isT=false);
298  SDValue getTargetConstantPool(Constant *C, MVT VT,
299                                  unsigned Align = 0, int Offset = 0) {
300    return getConstantPool(C, VT, Align, Offset, true);
301  }
302  SDValue getConstantPool(MachineConstantPoolValue *C, MVT VT,
303                            unsigned Align = 0, int Offs = 0, bool isT=false);
304  SDValue getTargetConstantPool(MachineConstantPoolValue *C,
305                                  MVT VT, unsigned Align = 0,
306                                  int Offset = 0) {
307    return getConstantPool(C, VT, Align, Offset, true);
308  }
309  SDValue getBasicBlock(MachineBasicBlock *MBB);
310  SDValue getBasicBlock(MachineBasicBlock *MBB, DebugLoc dl);
311  SDValue getExternalSymbol(const char *Sym, MVT VT);
312  SDValue getExternalSymbol(const char *Sym, DebugLoc dl, MVT VT);
313  SDValue getTargetExternalSymbol(const char *Sym, MVT VT);
314  SDValue getTargetExternalSymbol(const char *Sym, DebugLoc dl, MVT VT);
315  SDValue getArgFlags(ISD::ArgFlagsTy Flags);
316  SDValue getValueType(MVT);
317  SDValue getRegister(unsigned Reg, MVT VT);
318  SDValue getDbgStopPoint(SDValue Root, unsigned Line, unsigned Col,
319                          Value *CU);
320  SDValue getLabel(unsigned Opcode, SDValue Root, unsigned LabelID);
321  SDValue getLabel(unsigned Opcode, DebugLoc dl, SDValue Root,
322                   unsigned LabelID);
323
324  SDValue getCopyToReg(SDValue Chain, unsigned Reg, SDValue N) {
325    return getNode(ISD::CopyToReg, MVT::Other, Chain,
326                   getRegister(Reg, N.getValueType()), N);
327  }
328
329  // This version of the getCopyToReg method takes an extra operand, which
330  // indicates that there is potentially an incoming flag value (if Flag is not
331  // null) and that there should be a flag result.
332  SDValue getCopyToReg(SDValue Chain, unsigned Reg, SDValue N,
333                         SDValue Flag) {
334    const MVT *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
335    SDValue Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Flag };
336    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.getNode() ? 4 : 3);
337  }
338
339  // Similar to last getCopyToReg() except parameter Reg is a SDValue
340  SDValue getCopyToReg(SDValue Chain, SDValue Reg, SDValue N,
341                         SDValue Flag) {
342    const MVT *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
343    SDValue Ops[] = { Chain, Reg, N, Flag };
344    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.getNode() ? 4 : 3);
345  }
346
347  SDValue getCopyFromReg(SDValue Chain, unsigned Reg, MVT VT) {
348    const MVT *VTs = getNodeValueTypes(VT, MVT::Other);
349    SDValue Ops[] = { Chain, getRegister(Reg, VT) };
350    return getNode(ISD::CopyFromReg, VTs, 2, Ops, 2);
351  }
352
353  // This version of the getCopyFromReg method takes an extra operand, which
354  // indicates that there is potentially an incoming flag value (if Flag is not
355  // null) and that there should be a flag result.
356  SDValue getCopyFromReg(SDValue Chain, unsigned Reg, MVT VT,
357                           SDValue Flag) {
358    const MVT *VTs = getNodeValueTypes(VT, MVT::Other, MVT::Flag);
359    SDValue Ops[] = { Chain, getRegister(Reg, VT), Flag };
360    return getNode(ISD::CopyFromReg, VTs, 3, Ops, Flag.getNode() ? 3 : 2);
361  }
362
363  SDValue getCondCode(ISD::CondCode Cond);
364
365  /// Returns the ConvertRndSat Note: Avoid using this node because it may
366  /// disappear in the future and most targets don't support it.
367  SDValue getConvertRndSat(MVT VT, SDValue Val, SDValue DTy, SDValue STy,
368                           SDValue Rnd, SDValue Sat, ISD::CvtCode Code);
369
370  /// getZeroExtendInReg - Return the expression required to zero extend the Op
371  /// value assuming it was the smaller SrcTy value.
372  SDValue getZeroExtendInReg(SDValue Op, MVT SrcTy);
373  SDValue getZeroExtendInReg(SDValue Op, DebugLoc DL, MVT SrcTy);
374
375  /// getNOT - Create a bitwise NOT operation as (XOR Val, -1).
376  SDValue getNOT(DebugLoc DL, SDValue Val, MVT VT);
377
378  /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
379  /// a flag result (to ensure it's not CSE'd).
380  SDValue getCALLSEQ_START(SDValue Chain, SDValue Op) {
381    const MVT *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
382    SDValue Ops[] = { Chain,  Op };
383    return getNode(ISD::CALLSEQ_START, VTs, 2, Ops, 2);
384  }
385
386  /// getCALLSEQ_END - Return a new CALLSEQ_END node, which always must have a
387  /// flag result (to ensure it's not CSE'd).
388  SDValue getCALLSEQ_END(SDValue Chain, SDValue Op1, SDValue Op2,
389                           SDValue InFlag) {
390    SDVTList NodeTys = getVTList(MVT::Other, MVT::Flag);
391    SmallVector<SDValue, 4> Ops;
392    Ops.push_back(Chain);
393    Ops.push_back(Op1);
394    Ops.push_back(Op2);
395    Ops.push_back(InFlag);
396    return getNode(ISD::CALLSEQ_END, NodeTys, &Ops[0],
397                   (unsigned)Ops.size() - (InFlag.getNode() == 0 ? 1 : 0));
398  }
399
400  /// getNode - Gets or creates the specified node.
401  ///
402  SDValue getNode(unsigned Opcode, MVT VT);
403  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT);
404  SDValue getNode(unsigned Opcode, MVT VT, SDValue N);
405  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT, SDValue N);
406  SDValue getNode(unsigned Opcode, MVT VT, SDValue N1, SDValue N2);
407  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT, SDValue N1, SDValue N2);
408  SDValue getNode(unsigned Opcode, MVT VT,
409                  SDValue N1, SDValue N2, SDValue N3);
410  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT,
411                  SDValue N1, SDValue N2, SDValue N3);
412  SDValue getNode(unsigned Opcode, MVT VT,
413                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
414  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT,
415                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
416  SDValue getNode(unsigned Opcode, MVT VT,
417                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
418                  SDValue N5);
419  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT,
420                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
421                  SDValue N5);
422  SDValue getNode(unsigned Opcode, MVT VT,
423                  const SDUse *Ops, unsigned NumOps);
424  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT,
425                  const SDUse *Ops, unsigned NumOps);
426  SDValue getNode(unsigned Opcode, MVT VT,
427                  const SDValue *Ops, unsigned NumOps);
428  SDValue getNode(unsigned Opcode, DebugLoc DL, MVT VT,
429                  const SDValue *Ops, unsigned NumOps);
430  SDValue getNode(unsigned Opcode, const std::vector<MVT> &ResultTys,
431                  const SDValue *Ops, unsigned NumOps);
432  SDValue getNode(unsigned Opcode, DebugLoc DL,
433                  const std::vector<MVT> &ResultTys,
434                  const SDValue *Ops, unsigned NumOps);
435  SDValue getNode(unsigned Opcode, const MVT *VTs, unsigned NumVTs,
436                  const SDValue *Ops, unsigned NumOps);
437  SDValue getNode(unsigned Opcode, DebugLoc DL, const MVT *VTs, unsigned NumVTs,
438                  const SDValue *Ops, unsigned NumOps);
439  SDValue getNode(unsigned Opcode, SDVTList VTs,
440                  const SDValue *Ops, unsigned NumOps);
441  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
442                  const SDValue *Ops, unsigned NumOps);
443
444  SDValue getNode(unsigned Opcode, SDVTList VTs);
445  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs);
446  SDValue getNode(unsigned Opcode, SDVTList VTs, SDValue N);
447  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs, SDValue N);
448  SDValue getNode(unsigned Opcode, SDVTList VTs, SDValue N1, SDValue N2);
449  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
450                  SDValue N1, SDValue N2);
451  SDValue getNode(unsigned Opcode, SDVTList VTs,
452                  SDValue N1, SDValue N2, SDValue N3);
453  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
454                  SDValue N1, SDValue N2, SDValue N3);
455  SDValue getNode(unsigned Opcode, SDVTList VTs,
456                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
457  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
458                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
459  SDValue getNode(unsigned Opcode, SDVTList VTs,
460                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
461                  SDValue N5);
462  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
463                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
464                  SDValue N5);
465
466  SDValue getMemcpy(SDValue Chain, SDValue Dst, SDValue Src,
467                    SDValue Size, unsigned Align, bool AlwaysInline,
468                    const Value *DstSV, uint64_t DstSVOff,
469                    const Value *SrcSV, uint64_t SrcSVOff);
470
471  SDValue getMemmove(SDValue Chain, SDValue Dst, SDValue Src,
472                     SDValue Size, unsigned Align,
473                     const Value *DstSV, uint64_t DstOSVff,
474                     const Value *SrcSV, uint64_t SrcSVOff);
475
476  SDValue getMemset(SDValue Chain, SDValue Dst, SDValue Src,
477                    SDValue Size, unsigned Align,
478                    const Value *DstSV, uint64_t DstSVOff);
479
480  /// getSetCC - Helper function to make it easier to build SetCC's if you just
481  /// have an ISD::CondCode instead of an SDValue.
482  ///
483  SDValue getSetCC(MVT VT, SDValue LHS, SDValue RHS,
484                   ISD::CondCode Cond) {
485    return getNode(ISD::SETCC, DebugLoc::getUnknownLoc(), VT,
486                   LHS, RHS, getCondCode(Cond));
487  }
488  SDValue getSetCC(DebugLoc DL, MVT VT, SDValue LHS, SDValue RHS,
489                   ISD::CondCode Cond) {
490    return getNode(ISD::SETCC, DL, VT, LHS, RHS, getCondCode(Cond));
491  }
492
493  /// getVSetCC - Helper function to make it easier to build VSetCC's nodes
494  /// if you just have an ISD::CondCode instead of an SDValue.
495  ///
496  SDValue getVSetCC(MVT VT, SDValue LHS, SDValue RHS,
497                    ISD::CondCode Cond) {
498    return getNode(ISD::VSETCC, DebugLoc::getUnknownLoc(), VT,
499                   LHS, RHS, getCondCode(Cond));
500  }
501  SDValue getVSetCC(DebugLoc DL, MVT VT, SDValue LHS, SDValue RHS,
502                    ISD::CondCode Cond) {
503    return getNode(ISD::VSETCC, DL, VT, LHS, RHS, getCondCode(Cond));
504  }
505
506  /// getSelectCC - Helper function to make it easier to build SelectCC's if you
507  /// just have an ISD::CondCode instead of an SDValue.
508  ///
509  SDValue getSelectCC(SDValue LHS, SDValue RHS,
510                      SDValue True, SDValue False, ISD::CondCode Cond) {
511    return getNode(ISD::SELECT_CC, DebugLoc::getUnknownLoc(), True.getValueType(),
512                   LHS, RHS, True, False, getCondCode(Cond));
513  }
514  SDValue getSelectCC(DebugLoc DL, SDValue LHS, SDValue RHS,
515                      SDValue True, SDValue False, ISD::CondCode Cond) {
516    return getNode(ISD::SELECT_CC, DL, True.getValueType(),
517                   LHS, RHS, True, False, getCondCode(Cond));
518  }
519
520  /// getVAArg - VAArg produces a result and token chain, and takes a pointer
521  /// and a source value as input.
522  SDValue getVAArg(MVT VT, SDValue Chain, SDValue Ptr,
523                   SDValue SV);
524
525  /// getAtomic - Gets a node for an atomic op, produces result and chain and
526  /// takes 3 operands
527  SDValue getAtomic(unsigned Opcode, MVT MemVT, SDValue Chain, SDValue Ptr,
528                    SDValue Cmp, SDValue Swp, const Value* PtrVal,
529                    unsigned Alignment=0);
530  SDValue getAtomic(unsigned Opcode, DebugLoc dl, MVT MemVT, SDValue Chain,
531                    SDValue Ptr, SDValue Cmp, SDValue Swp, const Value* PtrVal,
532                    unsigned Alignment=0);
533
534  /// getAtomic - Gets a node for an atomic op, produces result and chain and
535  /// takes 2 operands.
536  SDValue getAtomic(unsigned Opcode, MVT MemVT, SDValue Chain, SDValue Ptr,
537                    SDValue Val, const Value* PtrVal,
538                    unsigned Alignment = 0);
539  SDValue getAtomic(unsigned Opcode, DebugLoc dl, MVT MemVT, SDValue Chain,
540                    SDValue Ptr, SDValue Val, const Value* PtrVal,
541                    unsigned Alignment = 0);
542
543  /// getMemIntrinsicNode - Creates a MemIntrinsicNode that may produce a
544  /// result and takes a list of operands.
545  SDValue getMemIntrinsicNode(unsigned Opcode,
546                              const MVT *VTs, unsigned NumVTs,
547                              const SDValue *Ops, unsigned NumOps,
548                              MVT MemVT, const Value *srcValue, int SVOff,
549                              unsigned Align = 0, bool Vol = false,
550                              bool ReadMem = true, bool WriteMem = true);
551  SDValue getMemIntrinsicNode(unsigned Opcode, DebugLoc dl,
552                              const MVT *VTs, unsigned NumVTs,
553                              const SDValue *Ops, unsigned NumOps,
554                              MVT MemVT, const Value *srcValue, int SVOff,
555                              unsigned Align = 0, bool Vol = false,
556                              bool ReadMem = true, bool WriteMem = true);
557
558  SDValue getMemIntrinsicNode(unsigned Opcode, SDVTList VTList,
559                              const SDValue *Ops, unsigned NumOps,
560                              MVT MemVT, const Value *srcValue, int SVOff,
561                              unsigned Align = 0, bool Vol = false,
562                              bool ReadMem = true, bool WriteMem = true);
563  SDValue getMemIntrinsicNode(unsigned Opcode, DebugLoc dl, SDVTList VTList,
564                              const SDValue *Ops, unsigned NumOps,
565                              MVT MemVT, const Value *srcValue, int SVOff,
566                              unsigned Align = 0, bool Vol = false,
567                              bool ReadMem = true, bool WriteMem = true);
568
569  /// getMergeValues - Create a MERGE_VALUES node from the given operands.
570  SDValue getMergeValues(const SDValue *Ops, unsigned NumOps);
571
572  /// getCall - Create a CALL node from the given information.
573  ///
574  SDValue getCall(unsigned CallingConv, bool IsVarArgs, bool IsTailCall,
575                  bool isInreg, SDVTList VTs, const SDValue *Operands,
576                  unsigned NumOperands);
577  SDValue getCall(unsigned CallingConv, DebugLoc dl, bool IsVarArgs,
578                  bool IsTailCall, bool isInreg, SDVTList VTs,
579                  const SDValue *Operands, unsigned NumOperands);
580
581  /// getLoad - Loads are not normal binary operators: their result type is not
582  /// determined by their operands, and they produce a value AND a token chain.
583  ///
584  SDValue getLoad(MVT VT, SDValue Chain, SDValue Ptr,
585                    const Value *SV, int SVOffset, bool isVolatile=false,
586                    unsigned Alignment=0);
587  SDValue getLoad(MVT VT, DebugLoc dl, SDValue Chain, SDValue Ptr,
588                    const Value *SV, int SVOffset, bool isVolatile=false,
589                    unsigned Alignment=0);
590  SDValue getExtLoad(ISD::LoadExtType ExtType, MVT VT,
591                       SDValue Chain, SDValue Ptr, const Value *SV,
592                       int SVOffset, MVT EVT, bool isVolatile=false,
593                       unsigned Alignment=0);
594  SDValue getExtLoad(ISD::LoadExtType ExtType, DebugLoc dl, MVT VT,
595                       SDValue Chain, SDValue Ptr, const Value *SV,
596                       int SVOffset, MVT EVT, bool isVolatile=false,
597                       unsigned Alignment=0);
598  SDValue getIndexedLoad(SDValue OrigLoad, SDValue Base,
599                           SDValue Offset, ISD::MemIndexedMode AM);
600  SDValue getIndexedLoad(SDValue OrigLoad, DebugLoc dl, SDValue Base,
601                           SDValue Offset, ISD::MemIndexedMode AM);
602  SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
603                    MVT VT, SDValue Chain,
604                    SDValue Ptr, SDValue Offset,
605                    const Value *SV, int SVOffset, MVT EVT,
606                    bool isVolatile=false, unsigned Alignment=0);
607  SDValue getLoad(ISD::MemIndexedMode AM, DebugLoc dl, ISD::LoadExtType ExtType,
608                    MVT VT, SDValue Chain,
609                    SDValue Ptr, SDValue Offset,
610                    const Value *SV, int SVOffset, MVT EVT,
611                    bool isVolatile=false, unsigned Alignment=0);
612
613  /// getStore - Helper function to build ISD::STORE nodes.
614  ///
615  SDValue getStore(SDValue Chain, SDValue Val, SDValue Ptr,
616                     const Value *SV, int SVOffset, bool isVolatile=false,
617                     unsigned Alignment=0);
618  SDValue getStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
619                     const Value *SV, int SVOffset, bool isVolatile=false,
620                     unsigned Alignment=0);
621  SDValue getTruncStore(SDValue Chain, SDValue Val, SDValue Ptr,
622                          const Value *SV, int SVOffset, MVT TVT,
623                          bool isVolatile=false, unsigned Alignment=0);
624  SDValue getTruncStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
625                          const Value *SV, int SVOffset, MVT TVT,
626                          bool isVolatile=false, unsigned Alignment=0);
627  SDValue getIndexedStore(SDValue OrigStoe, SDValue Base,
628                           SDValue Offset, ISD::MemIndexedMode AM);
629  SDValue getIndexedStore(SDValue OrigStoe, DebugLoc dl, SDValue Base,
630                           SDValue Offset, ISD::MemIndexedMode AM);
631
632  /// getSrcValue - Construct a node to track a Value* through the backend.
633  SDValue getSrcValue(const Value *v);
634
635  /// getMemOperand - Construct a node to track a memory reference
636  /// through the backend.
637  SDValue getMemOperand(const MachineMemOperand &MO);
638
639  /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
640  /// specified operands.  If the resultant node already exists in the DAG,
641  /// this does not modify the specified node, instead it returns the node that
642  /// already exists.  If the resultant node does not exist in the DAG, the
643  /// input node is returned.  As a degenerate case, if you specify the same
644  /// input operands as the node already has, the input node is returned.
645  SDValue UpdateNodeOperands(SDValue N, SDValue Op);
646  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2);
647  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
648                               SDValue Op3);
649  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
650                               SDValue Op3, SDValue Op4);
651  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
652                               SDValue Op3, SDValue Op4, SDValue Op5);
653  SDValue UpdateNodeOperands(SDValue N,
654                               const SDValue *Ops, unsigned NumOps);
655
656  /// SelectNodeTo - These are used for target selectors to *mutate* the
657  /// specified node to have the specified return type, Target opcode, and
658  /// operands.  Note that target opcodes are stored as
659  /// ~TargetOpcode in the node opcode field.  The resultant node is returned.
660  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT);
661  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT, SDValue Op1);
662  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT,
663                       SDValue Op1, SDValue Op2);
664  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT,
665                       SDValue Op1, SDValue Op2, SDValue Op3);
666  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT,
667                       const SDValue *Ops, unsigned NumOps);
668  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1, MVT VT2);
669  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
670                       MVT VT2, const SDValue *Ops, unsigned NumOps);
671  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
672                       MVT VT2, MVT VT3, const SDValue *Ops, unsigned NumOps);
673  SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, MVT VT1,
674                       MVT VT2, MVT VT3, MVT VT4, const SDValue *Ops,
675                       unsigned NumOps);
676  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
677                       MVT VT2, SDValue Op1);
678  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
679                       MVT VT2, SDValue Op1, SDValue Op2);
680  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
681                       MVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
682  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT VT1,
683                       MVT VT2, MVT VT3, SDValue Op1, SDValue Op2, SDValue Op3);
684  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, SDVTList VTs,
685                       const SDValue *Ops, unsigned NumOps);
686
687  /// MorphNodeTo - These *mutate* the specified node to have the specified
688  /// return type, opcode, and operands.
689  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT);
690  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT, SDValue Op1);
691  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT,
692                      SDValue Op1, SDValue Op2);
693  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT,
694                      SDValue Op1, SDValue Op2, SDValue Op3);
695  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT,
696                      const SDValue *Ops, unsigned NumOps);
697  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1, MVT VT2);
698  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1,
699                      MVT VT2, const SDValue *Ops, unsigned NumOps);
700  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1,
701                      MVT VT2, MVT VT3, const SDValue *Ops, unsigned NumOps);
702  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1,
703                      MVT VT2, SDValue Op1);
704  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1,
705                      MVT VT2, SDValue Op1, SDValue Op2);
706  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, MVT VT1,
707                      MVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
708  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, SDVTList VTs,
709                      const SDValue *Ops, unsigned NumOps);
710
711  /// getTargetNode - These are used for target selectors to create a new node
712  /// with specified return type(s), target opcode, and operands.
713  ///
714  /// Note that getTargetNode returns the resultant node.  If there is already a
715  /// node of the specified opcode and operands, it returns that node instead of
716  /// the current one.
717  SDNode *getTargetNode(unsigned Opcode, MVT VT);
718  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT);
719
720  SDNode *getTargetNode(unsigned Opcode, MVT VT, SDValue Op1);
721  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT, SDValue Op1);
722
723  SDNode *getTargetNode(unsigned Opcode, MVT VT, SDValue Op1, SDValue Op2);
724  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT, SDValue Op1,
725                        SDValue Op2);
726
727  SDNode *getTargetNode(unsigned Opcode, MVT VT,
728                        SDValue Op1, SDValue Op2, SDValue Op3);
729  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT,
730                        SDValue Op1, SDValue Op2, SDValue Op3);
731
732  SDNode *getTargetNode(unsigned Opcode, MVT VT,
733                        const SDValue *Ops, unsigned NumOps);
734  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT,
735                        const SDValue *Ops, unsigned NumOps);
736
737  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2);
738  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2);
739
740  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2, SDValue Op1);
741  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2,
742                        SDValue Op1);
743
744  SDNode *getTargetNode(unsigned Opcode, MVT VT1,
745                        MVT VT2, SDValue Op1, SDValue Op2);
746  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1,
747                        MVT VT2, SDValue Op1, SDValue Op2);
748
749  SDNode *getTargetNode(unsigned Opcode, MVT VT1,
750                        MVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
751  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1,
752                        MVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
753
754  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2,
755                        const SDValue *Ops, unsigned NumOps);
756  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2,
757                        const SDValue *Ops, unsigned NumOps);
758
759  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2, MVT VT3,
760                        SDValue Op1, SDValue Op2);
761  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2, MVT VT3,
762                        SDValue Op1, SDValue Op2);
763
764  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2, MVT VT3,
765                        SDValue Op1, SDValue Op2, SDValue Op3);
766  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2, MVT VT3,
767                        SDValue Op1, SDValue Op2, SDValue Op3);
768
769  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2, MVT VT3,
770                        const SDValue *Ops, unsigned NumOps);
771  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2, MVT VT3,
772                        const SDValue *Ops, unsigned NumOps);
773
774  SDNode *getTargetNode(unsigned Opcode, MVT VT1, MVT VT2, MVT VT3, MVT VT4,
775                        const SDValue *Ops, unsigned NumOps);
776  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl, MVT VT1, MVT VT2, MVT VT3,
777                        MVT VT4, const SDValue *Ops, unsigned NumOps);
778
779  SDNode *getTargetNode(unsigned Opcode, const std::vector<MVT> &ResultTys,
780                        const SDValue *Ops, unsigned NumOps);
781  SDNode *getTargetNode(unsigned Opcode, DebugLoc dl,
782                        const std::vector<MVT> &ResultTys, const SDValue *Ops,
783                        unsigned NumOps);
784
785  /// getNodeIfExists - Get the specified node if it's already available, or
786  /// else return NULL.
787  SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTs,
788                          const SDValue *Ops, unsigned NumOps);
789
790  /// DAGUpdateListener - Clients of various APIs that cause global effects on
791  /// the DAG can optionally implement this interface.  This allows the clients
792  /// to handle the various sorts of updates that happen.
793  class DAGUpdateListener {
794  public:
795    virtual ~DAGUpdateListener();
796
797    /// NodeDeleted - The node N that was deleted and, if E is not null, an
798    /// equivalent node E that replaced it.
799    virtual void NodeDeleted(SDNode *N, SDNode *E) = 0;
800
801    /// NodeUpdated - The node N that was updated.
802    virtual void NodeUpdated(SDNode *N) = 0;
803  };
804
805  /// RemoveDeadNode - Remove the specified node from the system. If any of its
806  /// operands then becomes dead, remove them as well. Inform UpdateListener
807  /// for each node deleted.
808  void RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener = 0);
809
810  /// RemoveDeadNodes - This method deletes the unreachable nodes in the
811  /// given list, and any nodes that become unreachable as a result.
812  void RemoveDeadNodes(SmallVectorImpl<SDNode *> &DeadNodes,
813                       DAGUpdateListener *UpdateListener = 0);
814
815  /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
816  /// This can cause recursive merging of nodes in the DAG.  Use the first
817  /// version if 'From' is known to have a single result, use the second
818  /// if you have two nodes with identical results, use the third otherwise.
819  ///
820  /// These methods all take an optional UpdateListener, which (if not null) is
821  /// informed about nodes that are deleted and modified due to recursive
822  /// changes in the dag.
823  ///
824  /// These functions only replace all existing uses. It's possible that as
825  /// these replacements are being performed, CSE may cause the From node
826  /// to be given new uses. These new uses of From are left in place, and
827  /// not automatically transfered to To.
828  ///
829  void ReplaceAllUsesWith(SDValue From, SDValue Op,
830                          DAGUpdateListener *UpdateListener = 0);
831  void ReplaceAllUsesWith(SDNode *From, SDNode *To,
832                          DAGUpdateListener *UpdateListener = 0);
833  void ReplaceAllUsesWith(SDNode *From, const SDValue *To,
834                          DAGUpdateListener *UpdateListener = 0);
835
836  /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
837  /// uses of other values produced by From.Val alone.
838  void ReplaceAllUsesOfValueWith(SDValue From, SDValue To,
839                                 DAGUpdateListener *UpdateListener = 0);
840
841  /// ReplaceAllUsesOfValuesWith - Like ReplaceAllUsesOfValueWith, but
842  /// for multiple values at once. This correctly handles the case where
843  /// there is an overlap between the From values and the To values.
844  void ReplaceAllUsesOfValuesWith(const SDValue *From, const SDValue *To,
845                                  unsigned Num,
846                                  DAGUpdateListener *UpdateListener = 0);
847
848  /// AssignTopologicalOrder - Topological-sort the AllNodes list and a
849  /// assign a unique node id for each node in the DAG based on their
850  /// topological order. Returns the number of nodes.
851  unsigned AssignTopologicalOrder();
852
853  /// RepositionNode - Move node N in the AllNodes list to be immediately
854  /// before the given iterator Position. This may be used to update the
855  /// topological ordering when the list of nodes is modified.
856  void RepositionNode(allnodes_iterator Position, SDNode *N) {
857    AllNodes.insert(Position, AllNodes.remove(N));
858  }
859
860  /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
861  /// operation.
862  static bool isCommutativeBinOp(unsigned Opcode) {
863    // FIXME: This should get its info from the td file, so that we can include
864    // target info.
865    switch (Opcode) {
866    case ISD::ADD:
867    case ISD::MUL:
868    case ISD::MULHU:
869    case ISD::MULHS:
870    case ISD::SMUL_LOHI:
871    case ISD::UMUL_LOHI:
872    case ISD::FADD:
873    case ISD::FMUL:
874    case ISD::AND:
875    case ISD::OR:
876    case ISD::XOR:
877    case ISD::ADDC:
878    case ISD::ADDE: return true;
879    default: return false;
880    }
881  }
882
883  void dump() const;
884
885  /// CreateStackTemporary - Create a stack temporary, suitable for holding the
886  /// specified value type.  If minAlign is specified, the slot size will have
887  /// at least that alignment.
888  SDValue CreateStackTemporary(MVT VT, unsigned minAlign = 1);
889
890  /// CreateStackTemporary - Create a stack temporary suitable for holding
891  /// either of the specified value types.
892  SDValue CreateStackTemporary(MVT VT1, MVT VT2);
893
894  /// FoldConstantArithmetic -
895  SDValue FoldConstantArithmetic(unsigned Opcode,
896                                 MVT VT,
897                                 ConstantSDNode *Cst1,
898                                 ConstantSDNode *Cst2);
899
900  /// FoldSetCC - Constant fold a setcc to true or false.
901  SDValue FoldSetCC(MVT VT, SDValue N1,
902                    SDValue N2, ISD::CondCode Cond);
903
904  /// SignBitIsZero - Return true if the sign bit of Op is known to be zero.  We
905  /// use this predicate to simplify operations downstream.
906  bool SignBitIsZero(SDValue Op, unsigned Depth = 0) const;
907
908  /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero.  We
909  /// use this predicate to simplify operations downstream.  Op and Mask are
910  /// known to be the same type.
911  bool MaskedValueIsZero(SDValue Op, const APInt &Mask, unsigned Depth = 0)
912    const;
913
914  /// ComputeMaskedBits - Determine which of the bits specified in Mask are
915  /// known to be either zero or one and return them in the KnownZero/KnownOne
916  /// bitsets.  This code only analyzes bits in Mask, in order to short-circuit
917  /// processing.  Targets can implement the computeMaskedBitsForTargetNode
918  /// method in the TargetLowering class to allow target nodes to be understood.
919  void ComputeMaskedBits(SDValue Op, const APInt &Mask, APInt &KnownZero,
920                         APInt &KnownOne, unsigned Depth = 0) const;
921
922  /// ComputeNumSignBits - Return the number of times the sign bit of the
923  /// register is replicated into the other bits.  We know that at least 1 bit
924  /// is always equal to the sign bit (itself), but other cases can give us
925  /// information.  For example, immediately after an "SRA X, 2", we know that
926  /// the top 3 bits are all equal to each other, so we return 3.  Targets can
927  /// implement the ComputeNumSignBitsForTarget method in the TargetLowering
928  /// class to allow target nodes to be understood.
929  unsigned ComputeNumSignBits(SDValue Op, unsigned Depth = 0) const;
930
931  /// isVerifiedDebugInfoDesc - Returns true if the specified SDValue has
932  /// been verified as a debug information descriptor.
933  bool isVerifiedDebugInfoDesc(SDValue Op) const;
934
935  /// getShuffleScalarElt - Returns the scalar element that will make up the ith
936  /// element of the result of the vector shuffle.
937  SDValue getShuffleScalarElt(const SDNode *N, unsigned Idx);
938
939private:
940  bool RemoveNodeFromCSEMaps(SDNode *N);
941  void AddModifiedNodeToCSEMaps(SDNode *N, DAGUpdateListener *UpdateListener);
942  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op, void *&InsertPos);
943  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op1, SDValue Op2,
944                               void *&InsertPos);
945  SDNode *FindModifiedNodeSlot(SDNode *N, const SDValue *Ops, unsigned NumOps,
946                               void *&InsertPos);
947
948  void DeleteNodeNotInCSEMaps(SDNode *N);
949  void DeallocateNode(SDNode *N);
950
951  unsigned getMVTAlignment(MVT MemoryVT) const;
952
953  void allnodes_clear();
954
955  /// VTList - List of non-single value types.
956  std::vector<SDVTList> VTList;
957
958  /// CondCodeNodes - Maps to auto-CSE operations.
959  std::vector<CondCodeSDNode*> CondCodeNodes;
960
961  std::vector<SDNode*> ValueTypeNodes;
962  std::map<MVT, SDNode*, MVT::compareRawBits> ExtendedValueTypeNodes;
963  StringMap<SDNode*> ExternalSymbols;
964  StringMap<SDNode*> TargetExternalSymbols;
965};
966
967template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
968  typedef SelectionDAG::allnodes_iterator nodes_iterator;
969  static nodes_iterator nodes_begin(SelectionDAG *G) {
970    return G->allnodes_begin();
971  }
972  static nodes_iterator nodes_end(SelectionDAG *G) {
973    return G->allnodes_end();
974  }
975};
976
977}  // end namespace llvm
978
979#endif
980