include/llvm/CodeGen/SelectionDAG.h

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