SelectionDAG.h revision c76909abfec876c6b751d693ebd3df07df686aa0 
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
29namespace llvm {
30
31class AliasAnalysis;
32class TargetLowering;
33class MachineModuleInfo;
34class DwarfWriter;
35class MachineFunction;
36class MachineConstantPoolValue;
37class FunctionLoweringInfo;
38
39template<> struct ilist_traits<SDNode> : public ilist_default_traits<SDNode> {
40private:
41  mutable ilist_half_node<SDNode> Sentinel;
42public:
43  SDNode *createSentinel() const {
44    return static_cast<SDNode*>(&Sentinel);
45  }
46  static void destroySentinel(SDNode *) {}
47
48  SDNode *provideInitialHead() const { return createSentinel(); }
49  SDNode *ensureHead(SDNode*) const { return createSentinel(); }
50  static void noteHead(SDNode*, SDNode*) {}
51
52  static void deleteNode(SDNode *) {
53    assert(0 && "ilist_traits<SDNode> shouldn't see a deleteNode call!");
54  }
55private:
56  static void createNode(const SDNode &);
57};
58
59enum CombineLevel {
60  Unrestricted,   // Combine may create illegal operations and illegal types.
61  NoIllegalTypes, // Combine may create illegal operations but no illegal types.
62  NoIllegalOperations // Combine may only create legal operations and types.
63};
64
65/// SelectionDAG class - This is used to represent a portion of an LLVM function
66/// in a low-level Data Dependence DAG representation suitable for instruction
67/// selection.  This DAG is constructed as the first step of instruction
68/// selection in order to allow implementation of machine specific optimizations
69/// and code simplifications.
70///
71/// The representation used by the SelectionDAG is a target-independent
72/// representation, which has some similarities to the GCC RTL representation,
73/// but is significantly more simple, powerful, and is a graph form instead of a
74/// linear form.
75///
76class SelectionDAG {
77  TargetLowering &TLI;
78  MachineFunction *MF;
79  FunctionLoweringInfo &FLI;
80  MachineModuleInfo *MMI;
81  DwarfWriter *DW;
82  LLVMContext* Context;
83
84  /// EntryNode - The starting token.
85  SDNode EntryNode;
86
87  /// Root - The root of the entire DAG.
88  SDValue Root;
89
90  /// AllNodes - A linked list of nodes in the current DAG.
91  ilist<SDNode> AllNodes;
92
93  /// NodeAllocatorType - The AllocatorType for allocating SDNodes. We use
94  /// pool allocation with recycling.
95  typedef RecyclingAllocator<BumpPtrAllocator, SDNode, sizeof(LargestSDNode),
96                             AlignOf<MostAlignedSDNode>::Alignment>
97    NodeAllocatorType;
98
99  /// NodeAllocator - Pool allocation for nodes.
100  NodeAllocatorType NodeAllocator;
101
102  /// CSEMap - This structure is used to memoize nodes, automatically performing
103  /// CSE with existing nodes when a duplicate is requested.
104  FoldingSet<SDNode> CSEMap;
105
106  /// OperandAllocator - Pool allocation for machine-opcode SDNode operands.
107  BumpPtrAllocator OperandAllocator;
108
109  /// Allocator - Pool allocation for misc. objects that are created once per
110  /// SelectionDAG.
111  BumpPtrAllocator Allocator;
112
113  /// VerifyNode - Sanity check the given node.  Aborts if it is invalid.
114  void VerifyNode(SDNode *N);
115
116  /// setGraphColorHelper - Implementation of setSubgraphColor.
117  /// Return whether we had to truncate the search.
118  ///
119  bool setSubgraphColorHelper(SDNode *N, const char *Color,
120                              DenseSet<SDNode *> &visited,
121                              int level, bool &printed);
122
123public:
124  SelectionDAG(TargetLowering &tli, FunctionLoweringInfo &fli);
125  ~SelectionDAG();
126
127  /// init - Prepare this SelectionDAG to process code in the given
128  /// MachineFunction.
129  ///
130  void init(MachineFunction &mf, MachineModuleInfo *mmi, DwarfWriter *dw);
131
132  /// clear - Clear state and free memory necessary to make this
133  /// SelectionDAG ready to process a new block.
134  ///
135  void clear();
136
137  MachineFunction &getMachineFunction() const { return *MF; }
138  const TargetMachine &getTarget() const;
139  TargetLowering &getTargetLoweringInfo() const { return TLI; }
140  FunctionLoweringInfo &getFunctionLoweringInfo() const { return FLI; }
141  MachineModuleInfo *getMachineModuleInfo() const { return MMI; }
142  DwarfWriter *getDwarfWriter() const { return DW; }
143  LLVMContext *getContext() const {return Context; }
144
145  /// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
146  ///
147  void viewGraph(const std::string &Title);
148  void viewGraph();
149
150#ifndef NDEBUG
151  std::map<const SDNode *, std::string> NodeGraphAttrs;
152#endif
153
154  /// clearGraphAttrs - Clear all previously defined node graph attributes.
155  /// Intended to be used from a debugging tool (eg. gdb).
156  void clearGraphAttrs();
157
158  /// setGraphAttrs - Set graph attributes for a node. (eg. "color=red".)
159  ///
160  void setGraphAttrs(const SDNode *N, const char *Attrs);
161
162  /// getGraphAttrs - Get graph attributes for a node. (eg. "color=red".)
163  /// Used from getNodeAttributes.
164  const std::string getGraphAttrs(const SDNode *N) const;
165
166  /// setGraphColor - Convenience for setting node color attribute.
167  ///
168  void setGraphColor(const SDNode *N, const char *Color);
169
170  /// setGraphColor - Convenience for setting subgraph color attribute.
171  ///
172  void setSubgraphColor(SDNode *N, const char *Color);
173
174  typedef ilist<SDNode>::const_iterator allnodes_const_iterator;
175  allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
176  allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }
177  typedef ilist<SDNode>::iterator allnodes_iterator;
178  allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
179  allnodes_iterator allnodes_end() { return AllNodes.end(); }
180  ilist<SDNode>::size_type allnodes_size() const {
181    return AllNodes.size();
182  }
183
184  /// getRoot - Return the root tag of the SelectionDAG.
185  ///
186  const SDValue &getRoot() const { return Root; }
187
188  /// getEntryNode - Return the token chain corresponding to the entry of the
189  /// function.
190  SDValue getEntryNode() const {
191    return SDValue(const_cast<SDNode *>(&EntryNode), 0);
192  }
193
194  /// setRoot - Set the current root tag of the SelectionDAG.
195  ///
196  const SDValue &setRoot(SDValue N) {
197    assert((!N.getNode() || N.getValueType() == MVT::Other) &&
198           "DAG root value is not a chain!");
199    return Root = N;
200  }
201
202  /// Combine - This iterates over the nodes in the SelectionDAG, folding
203  /// certain types of nodes together, or eliminating superfluous nodes.  The
204  /// Level argument controls whether Combine is allowed to produce nodes and
205  /// types that are illegal on the target.
206  void Combine(CombineLevel Level, AliasAnalysis &AA,
207               CodeGenOpt::Level OptLevel);
208
209  /// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that
210  /// only uses types natively supported by the target.  Returns "true" if it
211  /// made any changes.
212  ///
213  /// Note that this is an involved process that may invalidate pointers into
214  /// the graph.
215  bool LegalizeTypes();
216
217  /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
218  /// compatible with the target instruction selector, as indicated by the
219  /// TargetLowering object.
220  ///
221  /// Note that this is an involved process that may invalidate pointers into
222  /// the graph.
223  void Legalize(bool TypesNeedLegalizing, CodeGenOpt::Level OptLevel);
224
225  /// LegalizeVectors - This transforms the SelectionDAG into a SelectionDAG
226  /// that only uses vector math operations supported by the target.  This is
227  /// necessary as a separate step from Legalize because unrolling a vector
228  /// operation can introduce illegal types, which requires running
229  /// LegalizeTypes again.
230  ///
231  /// This returns true if it made any changes; in that case, LegalizeTypes
232  /// is called again before Legalize.
233  ///
234  /// Note that this is an involved process that may invalidate pointers into
235  /// the graph.
236  bool LegalizeVectors();
237
238  /// RemoveDeadNodes - This method deletes all unreachable nodes in the
239  /// SelectionDAG.
240  void RemoveDeadNodes();
241
242  /// DeleteNode - Remove the specified node from the system.  This node must
243  /// have no referrers.
244  void DeleteNode(SDNode *N);
245
246  /// getVTList - Return an SDVTList that represents the list of values
247  /// specified.
248  SDVTList getVTList(EVT VT);
249  SDVTList getVTList(EVT VT1, EVT VT2);
250  SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3);
251  SDVTList getVTList(EVT VT1, EVT VT2, EVT VT3, EVT VT4);
252  SDVTList getVTList(const EVT *VTs, unsigned NumVTs);
253
254  //===--------------------------------------------------------------------===//
255  // Node creation methods.
256  //
257  SDValue getConstant(uint64_t Val, EVT VT, bool isTarget = false);
258  SDValue getConstant(const APInt &Val, EVT VT, bool isTarget = false);
259  SDValue getConstant(const ConstantInt &Val, EVT VT, bool isTarget = false);
260  SDValue getIntPtrConstant(uint64_t Val, bool isTarget = false);
261  SDValue getTargetConstant(uint64_t Val, EVT VT) {
262    return getConstant(Val, VT, true);
263  }
264  SDValue getTargetConstant(const APInt &Val, EVT VT) {
265    return getConstant(Val, VT, true);
266  }
267  SDValue getTargetConstant(const ConstantInt &Val, EVT VT) {
268    return getConstant(Val, VT, true);
269  }
270  SDValue getConstantFP(double Val, EVT VT, bool isTarget = false);
271  SDValue getConstantFP(const APFloat& Val, EVT VT, bool isTarget = false);
272  SDValue getConstantFP(const ConstantFP &CF, EVT VT, bool isTarget = false);
273  SDValue getTargetConstantFP(double Val, EVT VT) {
274    return getConstantFP(Val, VT, true);
275  }
276  SDValue getTargetConstantFP(const APFloat& Val, EVT VT) {
277    return getConstantFP(Val, VT, true);
278  }
279  SDValue getTargetConstantFP(const ConstantFP &Val, EVT VT) {
280    return getConstantFP(Val, VT, true);
281  }
282  SDValue getGlobalAddress(const GlobalValue *GV, EVT VT,
283                           int64_t offset = 0, bool isTargetGA = false,
284                           unsigned char TargetFlags = 0);
285  SDValue getTargetGlobalAddress(const GlobalValue *GV, EVT VT,
286                                 int64_t offset = 0,
287                                 unsigned char TargetFlags = 0) {
288    return getGlobalAddress(GV, VT, offset, true, TargetFlags);
289  }
290  SDValue getFrameIndex(int FI, EVT VT, bool isTarget = false);
291  SDValue getTargetFrameIndex(int FI, EVT VT) {
292    return getFrameIndex(FI, VT, true);
293  }
294  SDValue getJumpTable(int JTI, EVT VT, bool isTarget = false,
295                       unsigned char TargetFlags = 0);
296  SDValue getTargetJumpTable(int JTI, EVT VT, unsigned char TargetFlags = 0) {
297    return getJumpTable(JTI, VT, true, TargetFlags);
298  }
299  SDValue getConstantPool(Constant *C, EVT VT,
300                          unsigned Align = 0, int Offs = 0, bool isT=false,
301                          unsigned char TargetFlags = 0);
302  SDValue getTargetConstantPool(Constant *C, EVT VT,
303                                unsigned Align = 0, int Offset = 0,
304                                unsigned char TargetFlags = 0) {
305    return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
306  }
307  SDValue getConstantPool(MachineConstantPoolValue *C, EVT VT,
308                          unsigned Align = 0, int Offs = 0, bool isT=false,
309                          unsigned char TargetFlags = 0);
310  SDValue getTargetConstantPool(MachineConstantPoolValue *C,
311                                  EVT VT, unsigned Align = 0,
312                                  int Offset = 0, unsigned char TargetFlags=0) {
313    return getConstantPool(C, VT, Align, Offset, true, TargetFlags);
314  }
315  // When generating a branch to a BB, we don't in general know enough
316  // to provide debug info for the BB at that time, so keep this one around.
317  SDValue getBasicBlock(MachineBasicBlock *MBB);
318  SDValue getBasicBlock(MachineBasicBlock *MBB, DebugLoc dl);
319  SDValue getExternalSymbol(const char *Sym, EVT VT);
320  SDValue getExternalSymbol(const char *Sym, DebugLoc dl, EVT VT);
321  SDValue getTargetExternalSymbol(const char *Sym, EVT VT,
322                                  unsigned char TargetFlags = 0);
323  SDValue getValueType(EVT);
324  SDValue getRegister(unsigned Reg, EVT VT);
325  SDValue getDbgStopPoint(DebugLoc DL, SDValue Root,
326                          unsigned Line, unsigned Col, MDNode *CU);
327  SDValue getLabel(unsigned Opcode, DebugLoc dl, SDValue Root,
328                   unsigned LabelID);
329
330  SDValue getCopyToReg(SDValue Chain, DebugLoc dl, unsigned Reg, SDValue N) {
331    return getNode(ISD::CopyToReg, dl, MVT::Other, Chain,
332                   getRegister(Reg, N.getValueType()), N);
333  }
334
335  // This version of the getCopyToReg method takes an extra operand, which
336  // indicates that there is potentially an incoming flag value (if Flag is not
337  // null) and that there should be a flag result.
338  SDValue getCopyToReg(SDValue Chain, DebugLoc dl, unsigned Reg, SDValue N,
339                       SDValue Flag) {
340    SDVTList VTs = getVTList(MVT::Other, MVT::Flag);
341    SDValue Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Flag };
342    return getNode(ISD::CopyToReg, dl, VTs, Ops, Flag.getNode() ? 4 : 3);
343  }
344
345  // Similar to last getCopyToReg() except parameter Reg is a SDValue
346  SDValue getCopyToReg(SDValue Chain, DebugLoc dl, SDValue Reg, SDValue N,
347                         SDValue Flag) {
348    SDVTList VTs = getVTList(MVT::Other, MVT::Flag);
349    SDValue Ops[] = { Chain, Reg, N, Flag };
350    return getNode(ISD::CopyToReg, dl, VTs, Ops, Flag.getNode() ? 4 : 3);
351  }
352
353  SDValue getCopyFromReg(SDValue Chain, DebugLoc dl, unsigned Reg, EVT VT) {
354    SDVTList VTs = getVTList(VT, MVT::Other);
355    SDValue Ops[] = { Chain, getRegister(Reg, VT) };
356    return getNode(ISD::CopyFromReg, dl, VTs, Ops, 2);
357  }
358
359  // This version of the getCopyFromReg method takes an extra operand, which
360  // indicates that there is potentially an incoming flag value (if Flag is not
361  // null) and that there should be a flag result.
362  SDValue getCopyFromReg(SDValue Chain, DebugLoc dl, unsigned Reg, EVT VT,
363                           SDValue Flag) {
364    SDVTList VTs = getVTList(VT, MVT::Other, MVT::Flag);
365    SDValue Ops[] = { Chain, getRegister(Reg, VT), Flag };
366    return getNode(ISD::CopyFromReg, dl, VTs, Ops, Flag.getNode() ? 3 : 2);
367  }
368
369  SDValue getCondCode(ISD::CondCode Cond);
370
371  /// Returns the ConvertRndSat Note: Avoid using this node because it may
372  /// disappear in the future and most targets don't support it.
373  SDValue getConvertRndSat(EVT VT, DebugLoc dl, SDValue Val, SDValue DTy,
374                           SDValue STy,
375                           SDValue Rnd, SDValue Sat, ISD::CvtCode Code);
376
377  /// getVectorShuffle - Return an ISD::VECTOR_SHUFFLE node.  The number of
378  /// elements in VT, which must be a vector type, must match the number of
379  /// mask elements NumElts.  A integer mask element equal to -1 is treated as
380  /// undefined.
381  SDValue getVectorShuffle(EVT VT, DebugLoc dl, SDValue N1, SDValue N2,
382                           const int *MaskElts);
383
384  /// getZeroExtendInReg - Return the expression required to zero extend the Op
385  /// value assuming it was the smaller SrcTy value.
386  SDValue getZeroExtendInReg(SDValue Op, DebugLoc DL, EVT SrcTy);
387
388  /// getNOT - Create a bitwise NOT operation as (XOR Val, -1).
389  SDValue getNOT(DebugLoc DL, SDValue Val, EVT VT);
390
391  /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
392  /// a flag result (to ensure it's not CSE'd).  CALLSEQ_START does not have a
393  /// useful DebugLoc.
394  SDValue getCALLSEQ_START(SDValue Chain, SDValue Op) {
395    SDVTList VTs = getVTList(MVT::Other, MVT::Flag);
396    SDValue Ops[] = { Chain,  Op };
397    return getNode(ISD::CALLSEQ_START, DebugLoc::getUnknownLoc(),
398                   VTs, Ops, 2);
399  }
400
401  /// getCALLSEQ_END - Return a new CALLSEQ_END node, which always must have a
402  /// flag result (to ensure it's not CSE'd).  CALLSEQ_END does not have
403  /// a useful DebugLoc.
404  SDValue getCALLSEQ_END(SDValue Chain, SDValue Op1, SDValue Op2,
405                           SDValue InFlag) {
406    SDVTList NodeTys = getVTList(MVT::Other, MVT::Flag);
407    SmallVector<SDValue, 4> Ops;
408    Ops.push_back(Chain);
409    Ops.push_back(Op1);
410    Ops.push_back(Op2);
411    Ops.push_back(InFlag);
412    return getNode(ISD::CALLSEQ_END, DebugLoc::getUnknownLoc(), NodeTys,
413                   &Ops[0],
414                   (unsigned)Ops.size() - (InFlag.getNode() == 0 ? 1 : 0));
415  }
416
417  /// getUNDEF - Return an UNDEF node.  UNDEF does not have a useful DebugLoc.
418  SDValue getUNDEF(EVT VT) {
419    return getNode(ISD::UNDEF, DebugLoc::getUnknownLoc(), VT);
420  }
421
422  /// getGLOBAL_OFFSET_TABLE - Return a GLOBAL_OFFSET_TABLE node.  This does
423  /// not have a useful DebugLoc.
424  SDValue getGLOBAL_OFFSET_TABLE(EVT VT) {
425    return getNode(ISD::GLOBAL_OFFSET_TABLE, DebugLoc::getUnknownLoc(), VT);
426  }
427
428  /// getNode - Gets or creates the specified node.
429  ///
430  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT);
431  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT, SDValue N);
432  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT, SDValue N1, SDValue N2);
433  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT,
434                  SDValue N1, SDValue N2, SDValue N3);
435  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT,
436                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
437  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT,
438                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
439                  SDValue N5);
440  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT,
441                  const SDUse *Ops, unsigned NumOps);
442  SDValue getNode(unsigned Opcode, DebugLoc DL, EVT VT,
443                  const SDValue *Ops, unsigned NumOps);
444  SDValue getNode(unsigned Opcode, DebugLoc DL,
445                  const std::vector<EVT> &ResultTys,
446                  const SDValue *Ops, unsigned NumOps);
447  SDValue getNode(unsigned Opcode, DebugLoc DL, const EVT *VTs, unsigned NumVTs,
448                  const SDValue *Ops, unsigned NumOps);
449  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
450                  const SDValue *Ops, unsigned NumOps);
451  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs);
452  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs, SDValue N);
453  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
454                  SDValue N1, SDValue N2);
455  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
456                  SDValue N1, SDValue N2, SDValue N3);
457  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
458                  SDValue N1, SDValue N2, SDValue N3, SDValue N4);
459  SDValue getNode(unsigned Opcode, DebugLoc DL, SDVTList VTs,
460                  SDValue N1, SDValue N2, SDValue N3, SDValue N4,
461                  SDValue N5);
462
463  /// getStackArgumentTokenFactor - Compute a TokenFactor to force all
464  /// the incoming stack arguments to be loaded from the stack. This is
465  /// used in tail call lowering to protect stack arguments from being
466  /// clobbered.
467  SDValue getStackArgumentTokenFactor(SDValue Chain);
468
469  SDValue getMemcpy(SDValue Chain, DebugLoc dl, SDValue Dst, SDValue Src,
470                    SDValue Size, unsigned Align, bool AlwaysInline,
471                    const Value *DstSV, uint64_t DstSVOff,
472                    const Value *SrcSV, uint64_t SrcSVOff);
473
474  SDValue getMemmove(SDValue Chain, DebugLoc dl, SDValue Dst, SDValue Src,
475                     SDValue Size, unsigned Align,
476                     const Value *DstSV, uint64_t DstOSVff,
477                     const Value *SrcSV, uint64_t SrcSVOff);
478
479  SDValue getMemset(SDValue Chain, DebugLoc dl, SDValue Dst, SDValue Src,
480                    SDValue Size, unsigned Align,
481                    const Value *DstSV, uint64_t DstSVOff);
482
483  /// getSetCC - Helper function to make it easier to build SetCC's if you just
484  /// have an ISD::CondCode instead of an SDValue.
485  ///
486  SDValue getSetCC(DebugLoc DL, EVT VT, SDValue LHS, SDValue RHS,
487                   ISD::CondCode Cond) {
488    return getNode(ISD::SETCC, DL, VT, LHS, RHS, getCondCode(Cond));
489  }
490
491  /// getVSetCC - Helper function to make it easier to build VSetCC's nodes
492  /// if you just have an ISD::CondCode instead of an SDValue.
493  ///
494  SDValue getVSetCC(DebugLoc DL, EVT VT, SDValue LHS, SDValue RHS,
495                    ISD::CondCode Cond) {
496    return getNode(ISD::VSETCC, DL, VT, LHS, RHS, getCondCode(Cond));
497  }
498
499  /// getSelectCC - Helper function to make it easier to build SelectCC's if you
500  /// just have an ISD::CondCode instead of an SDValue.
501  ///
502  SDValue getSelectCC(DebugLoc DL, SDValue LHS, SDValue RHS,
503                      SDValue True, SDValue False, ISD::CondCode Cond) {
504    return getNode(ISD::SELECT_CC, DL, True.getValueType(),
505                   LHS, RHS, True, False, getCondCode(Cond));
506  }
507
508  /// getVAArg - VAArg produces a result and token chain, and takes a pointer
509  /// and a source value as input.
510  SDValue getVAArg(EVT VT, DebugLoc dl, SDValue Chain, SDValue Ptr,
511                   SDValue SV);
512
513  /// getAtomic - Gets a node for an atomic op, produces result and chain and
514  /// takes 3 operands
515  SDValue getAtomic(unsigned Opcode, DebugLoc dl, EVT MemVT, SDValue Chain,
516                    SDValue Ptr, SDValue Cmp, SDValue Swp, const Value* PtrVal,
517                    unsigned Alignment=0);
518  SDValue getAtomic(unsigned Opcode, DebugLoc dl, EVT MemVT, SDValue Chain,
519                    SDValue Ptr, SDValue Cmp, SDValue Swp,
520                    MachineMemOperand *MMO);
521
522  /// getAtomic - Gets a node for an atomic op, produces result and chain and
523  /// takes 2 operands.
524  SDValue getAtomic(unsigned Opcode, DebugLoc dl, EVT MemVT, SDValue Chain,
525                    SDValue Ptr, SDValue Val, const Value* PtrVal,
526                    unsigned Alignment = 0);
527  SDValue getAtomic(unsigned Opcode, DebugLoc dl, EVT MemVT, SDValue Chain,
528                    SDValue Ptr, SDValue Val,
529                    MachineMemOperand *MMO);
530
531  /// getMemIntrinsicNode - Creates a MemIntrinsicNode that may produce a
532  /// result and takes a list of operands. Opcode may be INTRINSIC_VOID,
533  /// INTRINSIC_W_CHAIN, or a target-specific opcode with a value not
534  /// less than FIRST_TARGET_MEMORY_OPCODE.
535  SDValue getMemIntrinsicNode(unsigned Opcode, DebugLoc dl,
536                              const EVT *VTs, unsigned NumVTs,
537                              const SDValue *Ops, unsigned NumOps,
538                              EVT MemVT, const Value *srcValue, int SVOff,
539                              unsigned Align = 0, bool Vol = false,
540                              bool ReadMem = true, bool WriteMem = true);
541
542  SDValue getMemIntrinsicNode(unsigned Opcode, DebugLoc dl, SDVTList VTList,
543                              const SDValue *Ops, unsigned NumOps,
544                              EVT MemVT, const Value *srcValue, int SVOff,
545                              unsigned Align = 0, bool Vol = false,
546                              bool ReadMem = true, bool WriteMem = true);
547
548  SDValue getMemIntrinsicNode(unsigned Opcode, DebugLoc dl, SDVTList VTList,
549                              const SDValue *Ops, unsigned NumOps,
550                              EVT MemVT, MachineMemOperand *MMO);
551
552  /// getMergeValues - Create a MERGE_VALUES node from the given operands.
553  SDValue getMergeValues(const SDValue *Ops, unsigned NumOps, DebugLoc dl);
554
555  /// getLoad - Loads are not normal binary operators: their result type is not
556  /// determined by their operands, and they produce a value AND a token chain.
557  ///
558  SDValue getLoad(EVT VT, DebugLoc dl, SDValue Chain, SDValue Ptr,
559                    const Value *SV, int SVOffset, bool isVolatile=false,
560                    unsigned Alignment=0);
561  SDValue getExtLoad(ISD::LoadExtType ExtType, DebugLoc dl, EVT VT,
562                       SDValue Chain, SDValue Ptr, const Value *SV,
563                       int SVOffset, EVT MemVT, bool isVolatile=false,
564                       unsigned Alignment=0);
565  SDValue getIndexedLoad(SDValue OrigLoad, DebugLoc dl, SDValue Base,
566                           SDValue Offset, ISD::MemIndexedMode AM);
567  SDValue getLoad(ISD::MemIndexedMode AM, DebugLoc dl, ISD::LoadExtType ExtType,
568                  EVT VT, SDValue Chain, SDValue Ptr, SDValue Offset,
569                  const Value *SV, int SVOffset, EVT MemVT,
570                  bool isVolatile=false, unsigned Alignment=0);
571  SDValue getLoad(ISD::MemIndexedMode AM, DebugLoc dl, ISD::LoadExtType ExtType,
572                  EVT VT, SDValue Chain, SDValue Ptr, SDValue Offset,
573                  EVT MemVT, MachineMemOperand *MMO);
574
575  /// getStore - Helper function to build ISD::STORE nodes.
576  ///
577  SDValue getStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
578                     const Value *SV, int SVOffset, bool isVolatile=false,
579                     unsigned Alignment=0);
580  SDValue getStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
581                   MachineMemOperand *MMO);
582  SDValue getTruncStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
583                          const Value *SV, int SVOffset, EVT TVT,
584                          bool isVolatile=false, unsigned Alignment=0);
585  SDValue getTruncStore(SDValue Chain, DebugLoc dl, SDValue Val, SDValue Ptr,
586                        EVT TVT, MachineMemOperand *MMO);
587  SDValue getIndexedStore(SDValue OrigStoe, DebugLoc dl, SDValue Base,
588                           SDValue Offset, ISD::MemIndexedMode AM);
589
590  /// getSrcValue - Construct a node to track a Value* through the backend.
591  SDValue getSrcValue(const Value *v);
592
593  /// getShiftAmountOperand - Return the specified value casted to
594  /// the target's desired shift amount type.
595  SDValue getShiftAmountOperand(SDValue Op);
596
597  /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
598  /// specified operands.  If the resultant node already exists in the DAG,
599  /// this does not modify the specified node, instead it returns the node that
600  /// already exists.  If the resultant node does not exist in the DAG, the
601  /// input node is returned.  As a degenerate case, if you specify the same
602  /// input operands as the node already has, the input node is returned.
603  SDValue UpdateNodeOperands(SDValue N, SDValue Op);
604  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2);
605  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
606                               SDValue Op3);
607  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
608                               SDValue Op3, SDValue Op4);
609  SDValue UpdateNodeOperands(SDValue N, SDValue Op1, SDValue Op2,
610                               SDValue Op3, SDValue Op4, SDValue Op5);
611  SDValue UpdateNodeOperands(SDValue N,
612                               const SDValue *Ops, unsigned NumOps);
613
614  /// SelectNodeTo - These are used for target selectors to *mutate* the
615  /// specified node to have the specified return type, Target opcode, and
616  /// operands.  Note that target opcodes are stored as
617  /// ~TargetOpcode in the node opcode field.  The resultant node is returned.
618  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT);
619  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT, SDValue Op1);
620  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT,
621                       SDValue Op1, SDValue Op2);
622  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT,
623                       SDValue Op1, SDValue Op2, SDValue Op3);
624  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT,
625                       const SDValue *Ops, unsigned NumOps);
626  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1, EVT VT2);
627  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
628                       EVT VT2, const SDValue *Ops, unsigned NumOps);
629  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
630                       EVT VT2, EVT VT3, const SDValue *Ops, unsigned NumOps);
631  SDNode *SelectNodeTo(SDNode *N, unsigned MachineOpc, EVT VT1,
632                       EVT VT2, EVT VT3, EVT VT4, const SDValue *Ops,
633                       unsigned NumOps);
634  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
635                       EVT VT2, SDValue Op1);
636  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
637                       EVT VT2, SDValue Op1, SDValue Op2);
638  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
639                       EVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
640  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, EVT VT1,
641                       EVT VT2, EVT VT3, SDValue Op1, SDValue Op2, SDValue Op3);
642  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, SDVTList VTs,
643                       const SDValue *Ops, unsigned NumOps);
644
645  /// MorphNodeTo - These *mutate* the specified node to have the specified
646  /// return type, opcode, and operands.
647  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT);
648  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT, SDValue Op1);
649  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT,
650                      SDValue Op1, SDValue Op2);
651  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT,
652                      SDValue Op1, SDValue Op2, SDValue Op3);
653  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT,
654                      const SDValue *Ops, unsigned NumOps);
655  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1, EVT VT2);
656  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1,
657                      EVT VT2, const SDValue *Ops, unsigned NumOps);
658  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1,
659                      EVT VT2, EVT VT3, const SDValue *Ops, unsigned NumOps);
660  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1,
661                      EVT VT2, SDValue Op1);
662  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1,
663                      EVT VT2, SDValue Op1, SDValue Op2);
664  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, EVT VT1,
665                      EVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
666  SDNode *MorphNodeTo(SDNode *N, unsigned Opc, SDVTList VTs,
667                      const SDValue *Ops, unsigned NumOps);
668
669  /// getMachineNode - These are used for target selectors to create a new node
670  /// with specified return type(s), MachineInstr opcode, and operands.
671  ///
672  /// Note that getMachineNode returns the resultant node.  If there is already
673  /// a node of the specified opcode and operands, it returns that node instead
674  /// of the current one.
675  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT);
676  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT, SDValue Op1);
677  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT, SDValue Op1,
678                         SDValue Op2);
679  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT,
680                         SDValue Op1, SDValue Op2, SDValue Op3);
681  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT,
682                         const SDValue *Ops, unsigned NumOps);
683  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2);
684  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
685                         SDValue Op1);
686  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1,
687                         EVT VT2, SDValue Op1, SDValue Op2);
688  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1,
689                         EVT VT2, SDValue Op1, SDValue Op2, SDValue Op3);
690  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
691                         const SDValue *Ops, unsigned NumOps);
692  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
693                         EVT VT3, SDValue Op1, SDValue Op2);
694  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
695                         EVT VT3, SDValue Op1, SDValue Op2, SDValue Op3);
696  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
697                         EVT VT3, const SDValue *Ops, unsigned NumOps);
698  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, EVT VT1, EVT VT2,
699                         EVT VT3, EVT VT4, const SDValue *Ops, unsigned NumOps);
700  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl,
701                         const std::vector<EVT> &ResultTys, const SDValue *Ops,
702                         unsigned NumOps);
703  SDNode *getMachineNode(unsigned Opcode, DebugLoc dl, SDVTList VTs,
704                         const SDValue *Ops, unsigned NumOps);
705
706  /// getTargetExtractSubreg - A convenience function for creating
707  /// TargetInstrInfo::EXTRACT_SUBREG nodes.
708  SDValue getTargetExtractSubreg(int SRIdx, DebugLoc DL, EVT VT,
709                                 SDValue Operand);
710
711  /// getNodeIfExists - Get the specified node if it's already available, or
712  /// else return NULL.
713  SDNode *getNodeIfExists(unsigned Opcode, SDVTList VTs,
714                          const SDValue *Ops, unsigned NumOps);
715
716  /// DAGUpdateListener - Clients of various APIs that cause global effects on
717  /// the DAG can optionally implement this interface.  This allows the clients
718  /// to handle the various sorts of updates that happen.
719  class DAGUpdateListener {
720  public:
721    virtual ~DAGUpdateListener();
722
723    /// NodeDeleted - The node N that was deleted and, if E is not null, an
724    /// equivalent node E that replaced it.
725    virtual void NodeDeleted(SDNode *N, SDNode *E) = 0;
726
727    /// NodeUpdated - The node N that was updated.
728    virtual void NodeUpdated(SDNode *N) = 0;
729  };
730
731  /// RemoveDeadNode - Remove the specified node from the system. If any of its
732  /// operands then becomes dead, remove them as well. Inform UpdateListener
733  /// for each node deleted.
734  void RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener = 0);
735
736  /// RemoveDeadNodes - This method deletes the unreachable nodes in the
737  /// given list, and any nodes that become unreachable as a result.
738  void RemoveDeadNodes(SmallVectorImpl<SDNode *> &DeadNodes,
739                       DAGUpdateListener *UpdateListener = 0);
740
741  /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
742  /// This can cause recursive merging of nodes in the DAG.  Use the first
743  /// version if 'From' is known to have a single result, use the second
744  /// if you have two nodes with identical results (or if 'To' has a superset
745  /// of the results of 'From'), use the third otherwise.
746  ///
747  /// These methods all take an optional UpdateListener, which (if not null) is
748  /// informed about nodes that are deleted and modified due to recursive
749  /// changes in the dag.
750  ///
751  /// These functions only replace all existing uses. It's possible that as
752  /// these replacements are being performed, CSE may cause the From node
753  /// to be given new uses. These new uses of From are left in place, and
754  /// not automatically transfered to To.
755  ///
756  void ReplaceAllUsesWith(SDValue From, SDValue Op,
757                          DAGUpdateListener *UpdateListener = 0);
758  void ReplaceAllUsesWith(SDNode *From, SDNode *To,
759                          DAGUpdateListener *UpdateListener = 0);
760  void ReplaceAllUsesWith(SDNode *From, const SDValue *To,
761                          DAGUpdateListener *UpdateListener = 0);
762
763  /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
764  /// uses of other values produced by From.Val alone.
765  void ReplaceAllUsesOfValueWith(SDValue From, SDValue To,
766                                 DAGUpdateListener *UpdateListener = 0);
767
768  /// ReplaceAllUsesOfValuesWith - Like ReplaceAllUsesOfValueWith, but
769  /// for multiple values at once. This correctly handles the case where
770  /// there is an overlap between the From values and the To values.
771  void ReplaceAllUsesOfValuesWith(const SDValue *From, const SDValue *To,
772                                  unsigned Num,
773                                  DAGUpdateListener *UpdateListener = 0);
774
775  /// AssignTopologicalOrder - Topological-sort the AllNodes list and a
776  /// assign a unique node id for each node in the DAG based on their
777  /// topological order. Returns the number of nodes.
778  unsigned AssignTopologicalOrder();
779
780  /// RepositionNode - Move node N in the AllNodes list to be immediately
781  /// before the given iterator Position. This may be used to update the
782  /// topological ordering when the list of nodes is modified.
783  void RepositionNode(allnodes_iterator Position, SDNode *N) {
784    AllNodes.insert(Position, AllNodes.remove(N));
785  }
786
787  /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
788  /// operation.
789  static bool isCommutativeBinOp(unsigned Opcode) {
790    // FIXME: This should get its info from the td file, so that we can include
791    // target info.
792    switch (Opcode) {
793    case ISD::ADD:
794    case ISD::MUL:
795    case ISD::MULHU:
796    case ISD::MULHS:
797    case ISD::SMUL_LOHI:
798    case ISD::UMUL_LOHI:
799    case ISD::FADD:
800    case ISD::FMUL:
801    case ISD::AND:
802    case ISD::OR:
803    case ISD::XOR:
804    case ISD::SADDO:
805    case ISD::UADDO:
806    case ISD::ADDC:
807    case ISD::ADDE: return true;
808    default: return false;
809    }
810  }
811
812  void dump() const;
813
814  /// CreateStackTemporary - Create a stack temporary, suitable for holding the
815  /// specified value type.  If minAlign is specified, the slot size will have
816  /// at least that alignment.
817  SDValue CreateStackTemporary(EVT VT, unsigned minAlign = 1);
818
819  /// CreateStackTemporary - Create a stack temporary suitable for holding
820  /// either of the specified value types.
821  SDValue CreateStackTemporary(EVT VT1, EVT VT2);
822
823  /// FoldConstantArithmetic -
824  SDValue FoldConstantArithmetic(unsigned Opcode,
825                                 EVT VT,
826                                 ConstantSDNode *Cst1,
827                                 ConstantSDNode *Cst2);
828
829  /// FoldSetCC - Constant fold a setcc to true or false.
830  SDValue FoldSetCC(EVT VT, SDValue N1,
831                    SDValue N2, ISD::CondCode Cond, DebugLoc dl);
832
833  /// SignBitIsZero - Return true if the sign bit of Op is known to be zero.  We
834  /// use this predicate to simplify operations downstream.
835  bool SignBitIsZero(SDValue Op, unsigned Depth = 0) const;
836
837  /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero.  We
838  /// use this predicate to simplify operations downstream.  Op and Mask are
839  /// known to be the same type.
840  bool MaskedValueIsZero(SDValue Op, const APInt &Mask, unsigned Depth = 0)
841    const;
842
843  /// ComputeMaskedBits - Determine which of the bits specified in Mask are
844  /// known to be either zero or one and return them in the KnownZero/KnownOne
845  /// bitsets.  This code only analyzes bits in Mask, in order to short-circuit
846  /// processing.  Targets can implement the computeMaskedBitsForTargetNode
847  /// method in the TargetLowering class to allow target nodes to be understood.
848  void ComputeMaskedBits(SDValue Op, const APInt &Mask, APInt &KnownZero,
849                         APInt &KnownOne, unsigned Depth = 0) const;
850
851  /// ComputeNumSignBits - Return the number of times the sign bit of the
852  /// register is replicated into the other bits.  We know that at least 1 bit
853  /// is always equal to the sign bit (itself), but other cases can give us
854  /// information.  For example, immediately after an "SRA X, 2", we know that
855  /// the top 3 bits are all equal to each other, so we return 3.  Targets can
856  /// implement the ComputeNumSignBitsForTarget method in the TargetLowering
857  /// class to allow target nodes to be understood.
858  unsigned ComputeNumSignBits(SDValue Op, unsigned Depth = 0) const;
859
860  /// isKnownNeverNan - Test whether the given SDValue is known to never be NaN.
861  bool isKnownNeverNaN(SDValue Op) const;
862
863  /// isVerifiedDebugInfoDesc - Returns true if the specified SDValue has
864  /// been verified as a debug information descriptor.
865  bool isVerifiedDebugInfoDesc(SDValue Op) const;
866
867  /// getShuffleScalarElt - Returns the scalar element that will make up the ith
868  /// element of the result of the vector shuffle.
869  SDValue getShuffleScalarElt(const ShuffleVectorSDNode *N, unsigned Idx);
870
871private:
872  bool RemoveNodeFromCSEMaps(SDNode *N);
873  void AddModifiedNodeToCSEMaps(SDNode *N, DAGUpdateListener *UpdateListener);
874  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op, void *&InsertPos);
875  SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op1, SDValue Op2,
876                               void *&InsertPos);
877  SDNode *FindModifiedNodeSlot(SDNode *N, const SDValue *Ops, unsigned NumOps,
878                               void *&InsertPos);
879
880  void DeleteNodeNotInCSEMaps(SDNode *N);
881  void DeallocateNode(SDNode *N);
882
883  unsigned getEVTAlignment(EVT MemoryVT) const;
884
885  void allnodes_clear();
886
887  /// VTList - List of non-single value types.
888  std::vector<SDVTList> VTList;
889
890  /// CondCodeNodes - Maps to auto-CSE operations.
891  std::vector<CondCodeSDNode*> CondCodeNodes;
892
893  std::vector<SDNode*> ValueTypeNodes;
894  std::map<EVT, SDNode*, EVT::compareRawBits> ExtendedValueTypeNodes;
895  StringMap<SDNode*> ExternalSymbols;
896
897  std::map<std::pair<std::string, unsigned char>,SDNode*> TargetExternalSymbols;
898};
899
900template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
901  typedef SelectionDAG::allnodes_iterator nodes_iterator;
902  static nodes_iterator nodes_begin(SelectionDAG *G) {
903    return G->allnodes_begin();
904  }
905  static nodes_iterator nodes_end(SelectionDAG *G) {
906    return G->allnodes_end();
907  }
908};
909
910}  // end namespace llvm
911
912#endif
913