SelectionDAG.h revision ab0b949e0e9de452f3b052b11634ab761e008b23 
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/FoldingSet.h"
19#include "llvm/ADT/ilist"
20#include "llvm/CodeGen/SelectionDAGNodes.h"
21
22#include <list>
23#include <vector>
24#include <map>
25#include <set>
26#include <string>
27
28namespace llvm {
29  class AliasAnalysis;
30  class TargetLowering;
31  class TargetMachine;
32  class MachineModuleInfo;
33  class MachineFunction;
34  class MachineConstantPoolValue;
35
36/// SelectionDAG class - This is used to represent a portion of an LLVM function
37/// in a low-level Data Dependence DAG representation suitable for instruction
38/// selection.  This DAG is constructed as the first step of instruction
39/// selection in order to allow implementation of machine specific optimizations
40/// and code simplifications.
41///
42/// The representation used by the SelectionDAG is a target-independent
43/// representation, which has some similarities to the GCC RTL representation,
44/// but is significantly more simple, powerful, and is a graph form instead of a
45/// linear form.
46///
47class SelectionDAG {
48  TargetLowering &TLI;
49  MachineFunction &MF;
50  MachineModuleInfo *MMI;
51
52  /// Root - The root of the entire DAG.  EntryNode - The starting token.
53  SDOperand Root, EntryNode;
54
55  /// AllNodes - A linked list of nodes in the current DAG.
56  ilist<SDNode> AllNodes;
57
58  /// CSEMap - This structure is used to memoize nodes, automatically performing
59  /// CSE with existing nodes with a duplicate is requested.
60  FoldingSet<SDNode> CSEMap;
61
62public:
63  SelectionDAG(TargetLowering &tli, MachineFunction &mf, MachineModuleInfo *mmi)
64  : TLI(tli), MF(mf), MMI(mmi) {
65    EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
66  }
67  ~SelectionDAG();
68
69  MachineFunction &getMachineFunction() const { return MF; }
70  const TargetMachine &getTarget() const;
71  TargetLowering &getTargetLoweringInfo() const { return TLI; }
72  MachineModuleInfo *getMachineModuleInfo() const { return MMI; }
73
74  /// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
75  ///
76  void viewGraph();
77
78#ifndef NDEBUG
79  std::map<const SDNode *, std::string> NodeGraphAttrs;
80#endif
81
82  /// clearGraphAttrs - Clear all previously defined node graph attributes.
83  /// Intended to be used from a debugging tool (eg. gdb).
84  void clearGraphAttrs();
85
86  /// setGraphAttrs - Set graph attributes for a node. (eg. "color=red".)
87  ///
88  void setGraphAttrs(const SDNode *N, const char *Attrs);
89
90  /// getGraphAttrs - Get graph attributes for a node. (eg. "color=red".)
91  /// Used from getNodeAttributes.
92  const std::string getGraphAttrs(const SDNode *N) const;
93
94  /// setGraphColor - Convenience for setting node color attribute.
95  ///
96  void setGraphColor(const SDNode *N, const char *Color);
97
98  typedef ilist<SDNode>::const_iterator allnodes_const_iterator;
99  allnodes_const_iterator allnodes_begin() const { return AllNodes.begin(); }
100  allnodes_const_iterator allnodes_end() const { return AllNodes.end(); }
101  typedef ilist<SDNode>::iterator allnodes_iterator;
102  allnodes_iterator allnodes_begin() { return AllNodes.begin(); }
103  allnodes_iterator allnodes_end() { return AllNodes.end(); }
104
105  /// getRoot - Return the root tag of the SelectionDAG.
106  ///
107  const SDOperand &getRoot() const { return Root; }
108
109  /// getEntryNode - Return the token chain corresponding to the entry of the
110  /// function.
111  const SDOperand &getEntryNode() const { return EntryNode; }
112
113  /// setRoot - Set the current root tag of the SelectionDAG.
114  ///
115  const SDOperand &setRoot(SDOperand N) { return Root = N; }
116
117  /// Combine - This iterates over the nodes in the SelectionDAG, folding
118  /// certain types of nodes together, or eliminating superfluous nodes.  When
119  /// the AfterLegalize argument is set to 'true', Combine takes care not to
120  /// generate any nodes that will be illegal on the target.
121  void Combine(bool AfterLegalize, AliasAnalysis &AA);
122
123  /// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that
124  /// only uses types natively supported by the target.
125  ///
126  /// Note that this is an involved process that may invalidate pointers into
127  /// the graph.
128  void LegalizeTypes();
129
130  /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
131  /// compatible with the target instruction selector, as indicated by the
132  /// TargetLowering object.
133  ///
134  /// Note that this is an involved process that may invalidate pointers into
135  /// the graph.
136  void Legalize();
137
138  /// RemoveDeadNodes - This method deletes all unreachable nodes in the
139  /// SelectionDAG.
140  void RemoveDeadNodes();
141
142  /// DeleteNode - Remove the specified node from the system.  This node must
143  /// have no referrers.
144  void DeleteNode(SDNode *N);
145
146  /// getVTList - Return an SDVTList that represents the list of values
147  /// specified.
148  SDVTList getVTList(MVT::ValueType VT);
149  SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2);
150  SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2,MVT::ValueType VT3);
151  SDVTList getVTList(const MVT::ValueType *VTs, unsigned NumVTs);
152
153  /// getNodeValueTypes - These are obsolete, use getVTList instead.
154  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT) {
155    return getVTList(VT).VTs;
156  }
157  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,
158                                          MVT::ValueType VT2) {
159    return getVTList(VT1, VT2).VTs;
160  }
161  const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,MVT::ValueType VT2,
162                                          MVT::ValueType VT3) {
163    return getVTList(VT1, VT2, VT3).VTs;
164  }
165  const MVT::ValueType *getNodeValueTypes(std::vector<MVT::ValueType> &VTList) {
166    return getVTList(&VTList[0], VTList.size()).VTs;
167  }
168
169
170  //===--------------------------------------------------------------------===//
171  // Node creation methods.
172  //
173  SDOperand getString(const std::string &Val);
174  SDOperand getConstant(uint64_t Val, MVT::ValueType VT, bool isTarget = false);
175  SDOperand getConstant(const APInt &Val, MVT::ValueType VT, bool isTarget = false);
176  SDOperand getIntPtrConstant(uint64_t Val, bool isTarget = false);
177  SDOperand getTargetConstant(uint64_t Val, MVT::ValueType VT) {
178    return getConstant(Val, VT, true);
179  }
180  SDOperand getTargetConstant(const APInt &Val, MVT::ValueType VT) {
181    return getConstant(Val, VT, true);
182  }
183  SDOperand getConstantFP(double Val, MVT::ValueType VT, bool isTarget = false);
184  SDOperand getConstantFP(const APFloat& Val, MVT::ValueType VT,
185                          bool isTarget = false);
186  SDOperand getTargetConstantFP(double Val, MVT::ValueType VT) {
187    return getConstantFP(Val, VT, true);
188  }
189  SDOperand getTargetConstantFP(const APFloat& Val, MVT::ValueType VT) {
190    return getConstantFP(Val, VT, true);
191  }
192  SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
193                             int offset = 0, bool isTargetGA = false);
194  SDOperand getTargetGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
195                                   int offset = 0) {
196    return getGlobalAddress(GV, VT, offset, true);
197  }
198  SDOperand getFrameIndex(int FI, MVT::ValueType VT, bool isTarget = false);
199  SDOperand getTargetFrameIndex(int FI, MVT::ValueType VT) {
200    return getFrameIndex(FI, VT, true);
201  }
202  SDOperand getJumpTable(int JTI, MVT::ValueType VT, bool isTarget = false);
203  SDOperand getTargetJumpTable(int JTI, MVT::ValueType VT) {
204    return getJumpTable(JTI, VT, true);
205  }
206  SDOperand getConstantPool(Constant *C, MVT::ValueType VT,
207                            unsigned Align = 0, int Offs = 0, bool isT=false);
208  SDOperand getTargetConstantPool(Constant *C, MVT::ValueType VT,
209                                  unsigned Align = 0, int Offset = 0) {
210    return getConstantPool(C, VT, Align, Offset, true);
211  }
212  SDOperand getConstantPool(MachineConstantPoolValue *C, MVT::ValueType VT,
213                            unsigned Align = 0, int Offs = 0, bool isT=false);
214  SDOperand getTargetConstantPool(MachineConstantPoolValue *C,
215                                  MVT::ValueType VT, unsigned Align = 0,
216                                  int Offset = 0) {
217    return getConstantPool(C, VT, Align, Offset, true);
218  }
219  SDOperand getBasicBlock(MachineBasicBlock *MBB);
220  SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
221  SDOperand getTargetExternalSymbol(const char *Sym, MVT::ValueType VT);
222  SDOperand getValueType(MVT::ValueType);
223  SDOperand getRegister(unsigned Reg, MVT::ValueType VT);
224
225  SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N) {
226    return getNode(ISD::CopyToReg, MVT::Other, Chain,
227                   getRegister(Reg, N.getValueType()), N);
228  }
229
230  // This version of the getCopyToReg method takes an extra operand, which
231  // indicates that there is potentially an incoming flag value (if Flag is not
232  // null) and that there should be a flag result.
233  SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N,
234                         SDOperand Flag) {
235    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
236    SDOperand Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Flag };
237    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
238  }
239
240  // Similar to last getCopyToReg() except parameter Reg is a SDOperand
241  SDOperand getCopyToReg(SDOperand Chain, SDOperand Reg, SDOperand N,
242                         SDOperand Flag) {
243    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
244    SDOperand Ops[] = { Chain, Reg, N, Flag };
245    return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
246  }
247
248  SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
249    const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other);
250    SDOperand Ops[] = { Chain, getRegister(Reg, VT) };
251    return getNode(ISD::CopyFromReg, VTs, 2, Ops, 2);
252  }
253
254  // This version of the getCopyFromReg method takes an extra operand, which
255  // indicates that there is potentially an incoming flag value (if Flag is not
256  // null) and that there should be a flag result.
257  SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT,
258                           SDOperand Flag) {
259    const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other, MVT::Flag);
260    SDOperand Ops[] = { Chain, getRegister(Reg, VT), Flag };
261    return getNode(ISD::CopyFromReg, VTs, 3, Ops, Flag.Val ? 3 : 2);
262  }
263
264  SDOperand getCondCode(ISD::CondCode Cond);
265
266  /// getZeroExtendInReg - Return the expression required to zero extend the Op
267  /// value assuming it was the smaller SrcTy value.
268  SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
269
270  /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
271  /// a flag result (to ensure it's not CSE'd).
272  SDOperand getCALLSEQ_START(SDOperand Chain, SDOperand Op) {
273    const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
274    SDOperand Ops[] = { Chain,  Op };
275    return getNode(ISD::CALLSEQ_START, VTs, 2, Ops, 2);
276  }
277
278  /// getCALLSEQ_END - Return a new CALLSEQ_END node, which always must have a
279  /// flag result (to ensure it's not CSE'd).
280  SDOperand getCALLSEQ_END(SDOperand Chain, SDOperand Op1, SDOperand Op2,
281                           SDOperand InFlag) {
282    SDVTList NodeTys = getVTList(MVT::Other, MVT::Flag);
283    SmallVector<SDOperand, 4> Ops;
284    Ops.push_back(Chain);
285    Ops.push_back(Op1);
286    Ops.push_back(Op2);
287    Ops.push_back(InFlag);
288    return getNode(ISD::CALLSEQ_END, NodeTys, &Ops[0],
289                   Ops.size() - (InFlag.Val == 0 ? 1 : 0));
290  }
291
292  /// getNode - Gets or creates the specified node.
293  ///
294  SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
295  SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
296  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
297                    SDOperand N1, SDOperand N2);
298  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
299                    SDOperand N1, SDOperand N2, SDOperand N3);
300  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
301                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
302  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
303                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
304                    SDOperand N5);
305  SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
306                    const SDOperand *Ops, unsigned NumOps);
307  SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
308                    const SDOperand *Ops, unsigned NumOps);
309  SDOperand getNode(unsigned Opcode, const MVT::ValueType *VTs, unsigned NumVTs,
310                    const SDOperand *Ops, unsigned NumOps);
311  SDOperand getNode(unsigned Opcode, SDVTList VTs);
312  SDOperand getNode(unsigned Opcode, SDVTList VTs, SDOperand N);
313  SDOperand getNode(unsigned Opcode, SDVTList VTs,
314                    SDOperand N1, SDOperand N2);
315  SDOperand getNode(unsigned Opcode, SDVTList VTs,
316                    SDOperand N1, SDOperand N2, SDOperand N3);
317  SDOperand getNode(unsigned Opcode, SDVTList VTs,
318                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
319  SDOperand getNode(unsigned Opcode, SDVTList VTs,
320                    SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
321                    SDOperand N5);
322  SDOperand getNode(unsigned Opcode, SDVTList VTs,
323                    const SDOperand *Ops, unsigned NumOps);
324
325  SDOperand getMemcpy(SDOperand Chain, SDOperand Dest, SDOperand Src,
326                      SDOperand Size, SDOperand Align,
327                      SDOperand AlwaysInline);
328
329  SDOperand getMemmove(SDOperand Chain, SDOperand Dest, SDOperand Src,
330                      SDOperand Size, SDOperand Align,
331                      SDOperand AlwaysInline);
332
333  SDOperand getMemset(SDOperand Chain, SDOperand Dest, SDOperand Src,
334                      SDOperand Size, SDOperand Align,
335                      SDOperand AlwaysInline);
336
337  /// getSetCC - Helper function to make it easier to build SetCC's if you just
338  /// have an ISD::CondCode instead of an SDOperand.
339  ///
340  SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
341                     ISD::CondCode Cond) {
342    return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
343  }
344
345  /// getSelectCC - Helper function to make it easier to build SelectCC's if you
346  /// just have an ISD::CondCode instead of an SDOperand.
347  ///
348  SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
349                        SDOperand True, SDOperand False, ISD::CondCode Cond) {
350    return getNode(ISD::SELECT_CC, True.getValueType(), LHS, RHS, True, False,
351                   getCondCode(Cond));
352  }
353
354  /// getVAArg - VAArg produces a result and token chain, and takes a pointer
355  /// and a source value as input.
356  SDOperand getVAArg(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
357                     SDOperand SV);
358
359  /// getAtomic - Gets a node for an atomic op, produces result and chain, takes
360  // 3 operands
361  SDOperand getAtomic(unsigned Opcode, SDOperand Chain, SDOperand Ptr,
362                      SDOperand A2, SDOperand A3, MVT::ValueType VT);
363
364  /// getAtomic - Gets a node for an atomic op, produces result and chain, takes
365  // 2 operands
366  SDOperand getAtomic(unsigned Opcode, SDOperand Chain, SDOperand Ptr,
367                      SDOperand A2, MVT::ValueType VT);
368
369  /// getLoad - Loads are not normal binary operators: their result type is not
370  /// determined by their operands, and they produce a value AND a token chain.
371  ///
372  SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
373                    const Value *SV, int SVOffset, bool isVolatile=false,
374                    unsigned Alignment=0);
375  SDOperand getExtLoad(ISD::LoadExtType ExtType, MVT::ValueType VT,
376                       SDOperand Chain, SDOperand Ptr, const Value *SV,
377                       int SVOffset, MVT::ValueType EVT, bool isVolatile=false,
378                       unsigned Alignment=0);
379  SDOperand getIndexedLoad(SDOperand OrigLoad, SDOperand Base,
380                           SDOperand Offset, ISD::MemIndexedMode AM);
381
382  /// getStore - Helper function to build ISD::STORE nodes.
383  ///
384  SDOperand getStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
385                     const Value *SV, int SVOffset, bool isVolatile=false,
386                     unsigned Alignment=0);
387  SDOperand getTruncStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
388                          const Value *SV, int SVOffset, MVT::ValueType TVT,
389                          bool isVolatile=false, unsigned Alignment=0);
390  SDOperand getIndexedStore(SDOperand OrigStoe, SDOperand Base,
391                           SDOperand Offset, ISD::MemIndexedMode AM);
392
393  // getSrcValue - Construct a node to track a Value* through the backend.
394  SDOperand getSrcValue(const Value *v);
395
396  // getMemOperand - Construct a node to track a memory reference
397  // through the backend.
398  SDOperand getMemOperand(const MemOperand &MO);
399
400  /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
401  /// specified operands.  If the resultant node already exists in the DAG,
402  /// this does not modify the specified node, instead it returns the node that
403  /// already exists.  If the resultant node does not exist in the DAG, the
404  /// input node is returned.  As a degenerate case, if you specify the same
405  /// input operands as the node already has, the input node is returned.
406  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op);
407  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2);
408  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
409                               SDOperand Op3);
410  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
411                               SDOperand Op3, SDOperand Op4);
412  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
413                               SDOperand Op3, SDOperand Op4, SDOperand Op5);
414  SDOperand UpdateNodeOperands(SDOperand N, SDOperand *Ops, unsigned NumOps);
415
416  /// SelectNodeTo - These are used for target selectors to *mutate* the
417  /// specified node to have the specified return type, Target opcode, and
418  /// operands.  Note that target opcodes are stored as
419  /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field.  The 0th value
420  /// of the resultant node is returned.
421  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
422  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
423                       SDOperand Op1);
424  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
425                       SDOperand Op1, SDOperand Op2);
426  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
427                       SDOperand Op1, SDOperand Op2, SDOperand Op3);
428  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
429                        const SDOperand *Ops, unsigned NumOps);
430  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
431                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
432  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
433                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
434                       SDOperand Op3);
435
436
437  /// getTargetNode - These are used for target selectors to create a new node
438  /// with specified return type(s), target opcode, and operands.
439  ///
440  /// Note that getTargetNode returns the resultant node.  If there is already a
441  /// node of the specified opcode and operands, it returns that node instead of
442  /// the current one.
443  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT);
444  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
445                        SDOperand Op1);
446  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
447                        SDOperand Op1, SDOperand Op2);
448  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
449                        SDOperand Op1, SDOperand Op2, SDOperand Op3);
450  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
451                        const SDOperand *Ops, unsigned NumOps);
452  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
453                        MVT::ValueType VT2);
454  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
455                        MVT::ValueType VT2, SDOperand Op1);
456  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
457                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
458  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
459                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
460                        SDOperand Op3);
461  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
462                        MVT::ValueType VT2,
463                        const SDOperand *Ops, unsigned NumOps);
464  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
465                        MVT::ValueType VT2, MVT::ValueType VT3,
466                        SDOperand Op1, SDOperand Op2);
467  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
468                        MVT::ValueType VT2, MVT::ValueType VT3,
469                        SDOperand Op1, SDOperand Op2, SDOperand Op3);
470  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
471                        MVT::ValueType VT2, MVT::ValueType VT3,
472                        const SDOperand *Ops, unsigned NumOps);
473  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
474                        MVT::ValueType VT2, MVT::ValueType VT3,
475                        MVT::ValueType VT4,
476                        const SDOperand *Ops, unsigned NumOps);
477  SDNode *getTargetNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
478                        const SDOperand *Ops, unsigned NumOps);
479
480  /// DAGUpdateListener - Clients of various APIs that cause global effects on
481  /// the DAG can optionally implement this interface.  This allows the clients
482  /// to handle the various sorts of updates that happen.
483  class DAGUpdateListener {
484  public:
485    virtual ~DAGUpdateListener();
486    virtual void NodeDeleted(SDNode *N) = 0;
487    virtual void NodeUpdated(SDNode *N) = 0;
488  };
489
490  /// RemoveDeadNode - Remove the specified node from the system. If any of its
491  /// operands then becomes dead, remove them as well. Inform UpdateListener
492  /// for each node deleted.
493  void RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener = 0);
494
495  /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
496  /// This can cause recursive merging of nodes in the DAG.  Use the first
497  /// version if 'From' is known to have a single result, use the second
498  /// if you have two nodes with identical results, use the third otherwise.
499  ///
500  /// These methods all take an optional UpdateListener, which (if not null) is
501  /// informed about nodes that are deleted and modified due to recursive
502  /// changes in the dag.
503  ///
504  void ReplaceAllUsesWith(SDOperand From, SDOperand Op,
505                          DAGUpdateListener *UpdateListener = 0);
506  void ReplaceAllUsesWith(SDNode *From, SDNode *To,
507                          DAGUpdateListener *UpdateListener = 0);
508  void ReplaceAllUsesWith(SDNode *From, const SDOperand *To,
509                          DAGUpdateListener *UpdateListener = 0);
510
511  /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
512  /// uses of other values produced by From.Val alone.
513  void ReplaceAllUsesOfValueWith(SDOperand From, SDOperand To,
514                                 DAGUpdateListener *UpdateListener = 0);
515
516  /// AssignNodeIds - Assign a unique node id for each node in the DAG based on
517  /// their allnodes order. It returns the maximum id.
518  unsigned AssignNodeIds();
519
520  /// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
521  /// based on their topological order. It returns the maximum id and a vector
522  /// of the SDNodes* in assigned order by reference.
523  unsigned AssignTopologicalOrder(std::vector<SDNode*> &TopOrder);
524
525  /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
526  /// operation.
527  static bool isCommutativeBinOp(unsigned Opcode) {
528    // FIXME: This should get its info from the td file, so that we can include
529    // target info.
530    switch (Opcode) {
531    case ISD::ADD:
532    case ISD::MUL:
533    case ISD::MULHU:
534    case ISD::MULHS:
535    case ISD::SMUL_LOHI:
536    case ISD::UMUL_LOHI:
537    case ISD::FADD:
538    case ISD::FMUL:
539    case ISD::AND:
540    case ISD::OR:
541    case ISD::XOR:
542    case ISD::ADDC:
543    case ISD::ADDE: return true;
544    default: return false;
545    }
546  }
547
548  void dump() const;
549
550  /// CreateStackTemporary - Create a stack temporary, suitable for holding the
551  /// specified value type.
552  SDOperand CreateStackTemporary(MVT::ValueType VT);
553
554  /// FoldSetCC - Constant fold a setcc to true or false.
555  SDOperand FoldSetCC(MVT::ValueType VT, SDOperand N1,
556                      SDOperand N2, ISD::CondCode Cond);
557
558  /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero.  We
559  /// use this predicate to simplify operations downstream.  Op and Mask are
560  /// known to be the same type.
561  bool MaskedValueIsZero(SDOperand Op, uint64_t Mask, unsigned Depth = 0)
562    const;
563
564  /// ComputeMaskedBits - Determine which of the bits specified in Mask are
565  /// known to be either zero or one and return them in the KnownZero/KnownOne
566  /// bitsets.  This code only analyzes bits in Mask, in order to short-circuit
567  /// processing.  Targets can implement the computeMaskedBitsForTargetNode
568  /// method in the TargetLowering class to allow target nodes to be understood.
569  void ComputeMaskedBits(SDOperand Op, const APInt &Mask, APInt &KnownZero,
570                         APInt &KnownOne, unsigned Depth = 0) const;
571
572  /// ComputeMaskedBits - This is a wrapper around the APInt-using
573  /// form of ComputeMaskedBits for use by clients that haven't been converted
574  /// to APInt yet.
575  void ComputeMaskedBits(SDOperand Op, uint64_t Mask, uint64_t &KnownZero,
576                         uint64_t &KnownOne, unsigned Depth = 0) const;
577
578  /// ComputeNumSignBits - Return the number of times the sign bit of the
579  /// register is replicated into the other bits.  We know that at least 1 bit
580  /// is always equal to the sign bit (itself), but other cases can give us
581  /// information.  For example, immediately after an "SRA X, 2", we know that
582  /// the top 3 bits are all equal to each other, so we return 3.  Targets can
583  /// implement the ComputeNumSignBitsForTarget method in the TargetLowering
584  /// class to allow target nodes to be understood.
585  unsigned ComputeNumSignBits(SDOperand Op, unsigned Depth = 0) const;
586
587  /// isVerifiedDebugInfoDesc - Returns true if the specified SDOperand has
588  /// been verified as a debug information descriptor.
589  bool isVerifiedDebugInfoDesc(SDOperand Op) const;
590
591private:
592  void RemoveNodeFromCSEMaps(SDNode *N);
593  SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
594  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op, void *&InsertPos);
595  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op1, SDOperand Op2,
596                               void *&InsertPos);
597  SDNode *FindModifiedNodeSlot(SDNode *N, const SDOperand *Ops, unsigned NumOps,
598                               void *&InsertPos);
599
600  void DeleteNodeNotInCSEMaps(SDNode *N);
601
602  // List of non-single value types.
603  std::list<std::vector<MVT::ValueType> > VTList;
604
605  // Maps to auto-CSE operations.
606  std::vector<CondCodeSDNode*> CondCodeNodes;
607
608  std::vector<SDNode*> ValueTypeNodes;
609  std::map<MVT::ValueType, SDNode*> ExtendedValueTypeNodes;
610  std::map<std::string, SDNode*> ExternalSymbols;
611  std::map<std::string, SDNode*> TargetExternalSymbols;
612  std::map<std::string, StringSDNode*> StringNodes;
613};
614
615template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
616  typedef SelectionDAG::allnodes_iterator nodes_iterator;
617  static nodes_iterator nodes_begin(SelectionDAG *G) {
618    return G->allnodes_begin();
619  }
620  static nodes_iterator nodes_end(SelectionDAG *G) {
621    return G->allnodes_end();
622  }
623};
624
625}  // end namespace llvm
626
627#endif
628