SelectionDAG.h revision 6394b099e836f56a937cdcc7332c9487b504ca68 
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  /// getLoad - Loads are not normal binary operators: their result type is not
360  /// determined by their operands, and they produce a value AND a token chain.
361  ///
362  SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
363                    const Value *SV, int SVOffset, bool isVolatile=false,
364                    unsigned Alignment=0);
365  SDOperand getExtLoad(ISD::LoadExtType ExtType, MVT::ValueType VT,
366                       SDOperand Chain, SDOperand Ptr, const Value *SV,
367                       int SVOffset, MVT::ValueType EVT, bool isVolatile=false,
368                       unsigned Alignment=0);
369  SDOperand getIndexedLoad(SDOperand OrigLoad, SDOperand Base,
370                           SDOperand Offset, ISD::MemIndexedMode AM);
371
372  /// getStore - Helper function to build ISD::STORE nodes.
373  ///
374  SDOperand getStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
375                     const Value *SV, int SVOffset, bool isVolatile=false,
376                     unsigned Alignment=0);
377  SDOperand getTruncStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
378                          const Value *SV, int SVOffset, MVT::ValueType TVT,
379                          bool isVolatile=false, unsigned Alignment=0);
380  SDOperand getIndexedStore(SDOperand OrigStoe, SDOperand Base,
381                           SDOperand Offset, ISD::MemIndexedMode AM);
382
383  // getSrcValue - Construct a node to track a Value* through the backend.
384  SDOperand getSrcValue(const Value *v);
385
386  // getMemOperand - Construct a node to track a memory reference
387  // through the backend.
388  SDOperand getMemOperand(const MemOperand &MO);
389
390  /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
391  /// specified operands.  If the resultant node already exists in the DAG,
392  /// this does not modify the specified node, instead it returns the node that
393  /// already exists.  If the resultant node does not exist in the DAG, the
394  /// input node is returned.  As a degenerate case, if you specify the same
395  /// input operands as the node already has, the input node is returned.
396  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op);
397  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2);
398  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
399                               SDOperand Op3);
400  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
401                               SDOperand Op3, SDOperand Op4);
402  SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
403                               SDOperand Op3, SDOperand Op4, SDOperand Op5);
404  SDOperand UpdateNodeOperands(SDOperand N, SDOperand *Ops, unsigned NumOps);
405
406  /// SelectNodeTo - These are used for target selectors to *mutate* the
407  /// specified node to have the specified return type, Target opcode, and
408  /// operands.  Note that target opcodes are stored as
409  /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field.  The 0th value
410  /// of the resultant node is returned.
411  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
412  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
413                       SDOperand Op1);
414  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
415                       SDOperand Op1, SDOperand Op2);
416  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
417                       SDOperand Op1, SDOperand Op2, SDOperand Op3);
418  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
419                        const SDOperand *Ops, unsigned NumOps);
420  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
421                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
422  SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
423                       MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
424                       SDOperand Op3);
425
426
427  /// getTargetNode - These are used for target selectors to create a new node
428  /// with specified return type(s), target opcode, and operands.
429  ///
430  /// Note that getTargetNode returns the resultant node.  If there is already a
431  /// node of the specified opcode and operands, it returns that node instead of
432  /// the current one.
433  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT);
434  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
435                        SDOperand Op1);
436  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
437                        SDOperand Op1, SDOperand Op2);
438  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
439                        SDOperand Op1, SDOperand Op2, SDOperand Op3);
440  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
441                        const SDOperand *Ops, unsigned NumOps);
442  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
443                        MVT::ValueType VT2);
444  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
445                        MVT::ValueType VT2, SDOperand Op1);
446  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
447                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
448  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
449                        MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
450                        SDOperand Op3);
451  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
452                        MVT::ValueType VT2,
453                        const SDOperand *Ops, unsigned NumOps);
454  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
455                        MVT::ValueType VT2, MVT::ValueType VT3,
456                        SDOperand Op1, SDOperand Op2);
457  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
458                        MVT::ValueType VT2, MVT::ValueType VT3,
459                        SDOperand Op1, SDOperand Op2, SDOperand Op3);
460  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
461                        MVT::ValueType VT2, MVT::ValueType VT3,
462                        const SDOperand *Ops, unsigned NumOps);
463  SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
464                        MVT::ValueType VT2, MVT::ValueType VT3,
465                        MVT::ValueType VT4,
466                        const SDOperand *Ops, unsigned NumOps);
467  SDNode *getTargetNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
468                        const SDOperand *Ops, unsigned NumOps);
469
470  /// DAGUpdateListener - Clients of various APIs that cause global effects on
471  /// the DAG can optionally implement this interface.  This allows the clients
472  /// to handle the various sorts of updates that happen.
473  class DAGUpdateListener {
474  public:
475    virtual ~DAGUpdateListener();
476    virtual void NodeDeleted(SDNode *N) = 0;
477    virtual void NodeUpdated(SDNode *N) = 0;
478  };
479
480  /// RemoveDeadNode - Remove the specified node from the system. If any of its
481  /// operands then becomes dead, remove them as well. Inform UpdateListener
482  /// for each node deleted.
483  void RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener = 0);
484
485  /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
486  /// This can cause recursive merging of nodes in the DAG.  Use the first
487  /// version if 'From' is known to have a single result, use the second
488  /// if you have two nodes with identical results, use the third otherwise.
489  ///
490  /// These methods all take an optional UpdateListener, which (if not null) is
491  /// informed about nodes that are deleted and modified due to recursive
492  /// changes in the dag.
493  ///
494  void ReplaceAllUsesWith(SDOperand From, SDOperand Op,
495                          DAGUpdateListener *UpdateListener = 0);
496  void ReplaceAllUsesWith(SDNode *From, SDNode *To,
497                          DAGUpdateListener *UpdateListener = 0);
498  void ReplaceAllUsesWith(SDNode *From, const SDOperand *To,
499                          DAGUpdateListener *UpdateListener = 0);
500
501  /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
502  /// uses of other values produced by From.Val alone.
503  void ReplaceAllUsesOfValueWith(SDOperand From, SDOperand To,
504                                 DAGUpdateListener *UpdateListener = 0);
505
506  /// AssignNodeIds - Assign a unique node id for each node in the DAG based on
507  /// their allnodes order. It returns the maximum id.
508  unsigned AssignNodeIds();
509
510  /// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
511  /// based on their topological order. It returns the maximum id and a vector
512  /// of the SDNodes* in assigned order by reference.
513  unsigned AssignTopologicalOrder(std::vector<SDNode*> &TopOrder);
514
515  /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
516  /// operation.
517  static bool isCommutativeBinOp(unsigned Opcode) {
518    // FIXME: This should get its info from the td file, so that we can include
519    // target info.
520    switch (Opcode) {
521    case ISD::ADD:
522    case ISD::MUL:
523    case ISD::MULHU:
524    case ISD::MULHS:
525    case ISD::SMUL_LOHI:
526    case ISD::UMUL_LOHI:
527    case ISD::FADD:
528    case ISD::FMUL:
529    case ISD::AND:
530    case ISD::OR:
531    case ISD::XOR:
532    case ISD::ADDC:
533    case ISD::ADDE: return true;
534    default: return false;
535    }
536  }
537
538  void dump() const;
539
540  /// CreateStackTemporary - Create a stack temporary, suitable for holding the
541  /// specified value type.
542  SDOperand CreateStackTemporary(MVT::ValueType VT);
543
544  /// FoldSetCC - Constant fold a setcc to true or false.
545  SDOperand FoldSetCC(MVT::ValueType VT, SDOperand N1,
546                      SDOperand N2, ISD::CondCode Cond);
547
548  /// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero.  We
549  /// use this predicate to simplify operations downstream.  Op and Mask are
550  /// known to be the same type.
551  bool MaskedValueIsZero(SDOperand Op, uint64_t Mask, unsigned Depth = 0)
552    const;
553
554  /// ComputeMaskedBits - Determine which of the bits specified in Mask are
555  /// known to be either zero or one and return them in the KnownZero/KnownOne
556  /// bitsets.  This code only analyzes bits in Mask, in order to short-circuit
557  /// processing.  Targets can implement the computeMaskedBitsForTargetNode
558  /// method in the TargetLowering class to allow target nodes to be understood.
559  void ComputeMaskedBits(SDOperand Op, uint64_t Mask, uint64_t &KnownZero,
560                         uint64_t &KnownOne, unsigned Depth = 0) const;
561
562  /// ComputeNumSignBits - Return the number of times the sign bit of the
563  /// register is replicated into the other bits.  We know that at least 1 bit
564  /// is always equal to the sign bit (itself), but other cases can give us
565  /// information.  For example, immediately after an "SRA X, 2", we know that
566  /// the top 3 bits are all equal to each other, so we return 3.  Targets can
567  /// implement the ComputeNumSignBitsForTarget method in the TargetLowering
568  /// class to allow target nodes to be understood.
569  unsigned ComputeNumSignBits(SDOperand Op, unsigned Depth = 0) const;
570
571  /// isVerifiedDebugInfoDesc - Returns true if the specified SDOperand has
572  /// been verified as a debug information descriptor.
573  bool isVerifiedDebugInfoDesc(SDOperand Op) const;
574
575private:
576  void RemoveNodeFromCSEMaps(SDNode *N);
577  SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
578  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op, void *&InsertPos);
579  SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op1, SDOperand Op2,
580                               void *&InsertPos);
581  SDNode *FindModifiedNodeSlot(SDNode *N, const SDOperand *Ops, unsigned NumOps,
582                               void *&InsertPos);
583
584  void DeleteNodeNotInCSEMaps(SDNode *N);
585
586  // List of non-single value types.
587  std::list<std::vector<MVT::ValueType> > VTList;
588
589  // Maps to auto-CSE operations.
590  std::vector<CondCodeSDNode*> CondCodeNodes;
591
592  std::vector<SDNode*> ValueTypeNodes;
593  std::map<MVT::ValueType, SDNode*> ExtendedValueTypeNodes;
594  std::map<std::string, SDNode*> ExternalSymbols;
595  std::map<std::string, SDNode*> TargetExternalSymbols;
596  std::map<std::string, StringSDNode*> StringNodes;
597};
598
599template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
600  typedef SelectionDAG::allnodes_iterator nodes_iterator;
601  static nodes_iterator nodes_begin(SelectionDAG *G) {
602    return G->allnodes_begin();
603  }
604  static nodes_iterator nodes_end(SelectionDAG *G) {
605    return G->allnodes_end();
606  }
607};
608
609}  // end namespace llvm
610
611#endif
612