1 //===-- llvm/CodeGen/SelectionDAG.h - InstSelection DAG ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the SelectionDAG class, and transitively defines the
11 // SDNode class and subclasses.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_SELECTIONDAG_H
16 #define LLVM_CODEGEN_SELECTIONDAG_H
18 #include "llvm/ADT/FoldingSet.h"
19 #include "llvm/ADT/ilist"
20 #include "llvm/CodeGen/SelectionDAGNodes.h"
32 class MachineModuleInfo;
33 class MachineFunction;
34 class MachineConstantPoolValue;
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.
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
50 MachineModuleInfo *MMI;
52 /// Root - The root of the entire DAG. EntryNode - The starting token.
53 SDOperand Root, EntryNode;
55 /// AllNodes - A linked list of nodes in the current DAG.
56 ilist<SDNode> AllNodes;
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;
63 SelectionDAG(TargetLowering &tli, MachineFunction &mf, MachineModuleInfo *mmi)
64 : TLI(tli), MF(mf), MMI(mmi) {
65 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
69 MachineFunction &getMachineFunction() const { return MF; }
70 const TargetMachine &getTarget() const;
71 TargetLowering &getTargetLoweringInfo() const { return TLI; }
72 MachineModuleInfo *getMachineModuleInfo() const { return MMI; }
74 /// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
79 std::map<const SDNode *, std::string> NodeGraphAttrs;
82 /// clearGraphAttrs - Clear all previously defined node graph attributes.
83 /// Intended to be used from a debugging tool (eg. gdb).
84 void clearGraphAttrs();
86 /// setGraphAttrs - Set graph attributes for a node. (eg. "color=red".)
88 void setGraphAttrs(const SDNode *N, const char *Attrs);
90 /// getGraphAttrs - Get graph attributes for a node. (eg. "color=red".)
91 /// Used from getNodeAttributes.
92 const std::string getGraphAttrs(const SDNode *N) const;
94 /// setGraphColor - Convenience for setting node color attribute.
96 void setGraphColor(const SDNode *N, const char *Color);
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(); }
105 /// getRoot - Return the root tag of the SelectionDAG.
107 const SDOperand &getRoot() const { return Root; }
109 /// getEntryNode - Return the token chain corresponding to the entry of the
111 const SDOperand &getEntryNode() const { return EntryNode; }
113 /// setRoot - Set the current root tag of the SelectionDAG.
115 const SDOperand &setRoot(SDOperand N) { return Root = N; }
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);
123 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
124 /// compatible with the target instruction selector, as indicated by the
125 /// TargetLowering object.
127 /// Note that this is an involved process that may invalidate pointers into
131 /// RemoveDeadNodes - This method deletes all unreachable nodes in the
133 void RemoveDeadNodes();
135 /// RemoveDeadNode - Remove the specified node from the system. If any of its
136 /// operands then becomes dead, remove them as well. The vector Deleted is
137 /// populated with nodes that are deleted.
138 void RemoveDeadNode(SDNode *N, std::vector<SDNode*> &Deleted);
140 /// DeleteNode - Remove the specified node from the system. This node must
141 /// have no referrers.
142 void DeleteNode(SDNode *N);
144 /// getVTList - Return an SDVTList that represents the list of values
146 SDVTList getVTList(MVT::ValueType VT);
147 SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2);
148 SDVTList getVTList(MVT::ValueType VT1, MVT::ValueType VT2,MVT::ValueType VT3);
149 SDVTList getVTList(const MVT::ValueType *VTs, unsigned NumVTs);
151 /// getNodeValueTypes - These are obsolete, use getVTList instead.
152 const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT) {
153 return getVTList(VT).VTs;
155 const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,
156 MVT::ValueType VT2) {
157 return getVTList(VT1, VT2).VTs;
159 const MVT::ValueType *getNodeValueTypes(MVT::ValueType VT1,MVT::ValueType VT2,
160 MVT::ValueType VT3) {
161 return getVTList(VT1, VT2, VT3).VTs;
163 const MVT::ValueType *getNodeValueTypes(std::vector<MVT::ValueType> &VTList) {
164 return getVTList(&VTList[0], VTList.size()).VTs;
168 //===--------------------------------------------------------------------===//
169 // Node creation methods.
171 SDOperand getString(const std::string &Val);
172 SDOperand getConstant(uint64_t Val, MVT::ValueType VT, bool isTarget = false);
173 SDOperand getTargetConstant(uint64_t Val, MVT::ValueType VT) {
174 return getConstant(Val, VT, true);
176 SDOperand getConstantFP(double Val, MVT::ValueType VT, bool isTarget = false);
177 SDOperand getTargetConstantFP(double Val, MVT::ValueType VT) {
178 return getConstantFP(Val, VT, true);
180 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
181 int offset = 0, bool isTargetGA = false);
182 SDOperand getTargetGlobalAddress(const GlobalValue *GV, MVT::ValueType VT,
184 return getGlobalAddress(GV, VT, offset, true);
186 SDOperand getFrameIndex(int FI, MVT::ValueType VT, bool isTarget = false);
187 SDOperand getTargetFrameIndex(int FI, MVT::ValueType VT) {
188 return getFrameIndex(FI, VT, true);
190 SDOperand getJumpTable(int JTI, MVT::ValueType VT, bool isTarget = false);
191 SDOperand getTargetJumpTable(int JTI, MVT::ValueType VT) {
192 return getJumpTable(JTI, VT, true);
194 SDOperand getConstantPool(Constant *C, MVT::ValueType VT,
195 unsigned Align = 0, int Offs = 0, bool isT=false);
196 SDOperand getTargetConstantPool(Constant *C, MVT::ValueType VT,
197 unsigned Align = 0, int Offset = 0) {
198 return getConstantPool(C, VT, Align, Offset, true);
200 SDOperand getConstantPool(MachineConstantPoolValue *C, MVT::ValueType VT,
201 unsigned Align = 0, int Offs = 0, bool isT=false);
202 SDOperand getTargetConstantPool(MachineConstantPoolValue *C,
203 MVT::ValueType VT, unsigned Align = 0,
205 return getConstantPool(C, VT, Align, Offset, true);
207 SDOperand getBasicBlock(MachineBasicBlock *MBB);
208 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
209 SDOperand getTargetExternalSymbol(const char *Sym, MVT::ValueType VT);
210 SDOperand getValueType(MVT::ValueType);
211 SDOperand getRegister(unsigned Reg, MVT::ValueType VT);
213 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N) {
214 return getNode(ISD::CopyToReg, MVT::Other, Chain,
215 getRegister(Reg, N.getValueType()), N);
218 // This version of the getCopyToReg method takes an extra operand, which
219 // indicates that there is potentially an incoming flag value (if Flag is not
220 // null) and that there should be a flag result.
221 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N,
223 const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
224 SDOperand Ops[] = { Chain, getRegister(Reg, N.getValueType()), N, Flag };
225 return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
228 // Similar to last getCopyToReg() except parameter Reg is a SDOperand
229 SDOperand getCopyToReg(SDOperand Chain, SDOperand Reg, SDOperand N,
231 const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
232 SDOperand Ops[] = { Chain, Reg, N, Flag };
233 return getNode(ISD::CopyToReg, VTs, 2, Ops, Flag.Val ? 4 : 3);
236 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
237 const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other);
238 SDOperand Ops[] = { Chain, getRegister(Reg, VT) };
239 return getNode(ISD::CopyFromReg, VTs, 2, Ops, 2);
242 // This version of the getCopyFromReg method takes an extra operand, which
243 // indicates that there is potentially an incoming flag value (if Flag is not
244 // null) and that there should be a flag result.
245 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT,
247 const MVT::ValueType *VTs = getNodeValueTypes(VT, MVT::Other, MVT::Flag);
248 SDOperand Ops[] = { Chain, getRegister(Reg, VT), Flag };
249 return getNode(ISD::CopyFromReg, VTs, 3, Ops, Flag.Val ? 3 : 2);
252 SDOperand getCondCode(ISD::CondCode Cond);
254 /// getZeroExtendInReg - Return the expression required to zero extend the Op
255 /// value assuming it was the smaller SrcTy value.
256 SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
258 /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
259 /// a flag result (to ensure it's not CSE'd).
260 SDOperand getCALLSEQ_START(SDOperand Chain, SDOperand Op) {
261 const MVT::ValueType *VTs = getNodeValueTypes(MVT::Other, MVT::Flag);
262 SDOperand Ops[] = { Chain, Op };
263 return getNode(ISD::CALLSEQ_START, VTs, 2, Ops, 2);
266 /// getNode - Gets or creates the specified node.
268 SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
269 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
270 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
271 SDOperand N1, SDOperand N2);
272 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
273 SDOperand N1, SDOperand N2, SDOperand N3);
274 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
275 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
276 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
277 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
279 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
280 const SDOperand *Ops, unsigned NumOps);
281 SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
282 const SDOperand *Ops, unsigned NumOps);
283 SDOperand getNode(unsigned Opcode, const MVT::ValueType *VTs, unsigned NumVTs,
284 const SDOperand *Ops, unsigned NumOps);
285 SDOperand getNode(unsigned Opcode, SDVTList VTs,
286 const SDOperand *Ops, unsigned NumOps);
288 /// getSetCC - Helper function to make it easier to build SetCC's if you just
289 /// have an ISD::CondCode instead of an SDOperand.
291 SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
292 ISD::CondCode Cond) {
293 return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
296 /// getSelectCC - Helper function to make it easier to build SelectCC's if you
297 /// just have an ISD::CondCode instead of an SDOperand.
299 SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
300 SDOperand True, SDOperand False, ISD::CondCode Cond) {
301 return getNode(ISD::SELECT_CC, True.getValueType(), LHS, RHS, True, False,
305 /// getVAArg - VAArg produces a result and token chain, and takes a pointer
306 /// and a source value as input.
307 SDOperand getVAArg(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
310 /// getLoad - Loads are not normal binary operators: their result type is not
311 /// determined by their operands, and they produce a value AND a token chain.
313 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
314 const Value *SV, int SVOffset, bool isVolatile=false,
315 unsigned Alignment=0);
316 SDOperand getExtLoad(ISD::LoadExtType ExtType, MVT::ValueType VT,
317 SDOperand Chain, SDOperand Ptr, const Value *SV,
318 int SVOffset, MVT::ValueType EVT, bool isVolatile=false,
319 unsigned Alignment=0);
320 SDOperand getIndexedLoad(SDOperand OrigLoad, SDOperand Base,
321 SDOperand Offset, ISD::MemIndexedMode AM);
322 SDOperand getVecLoad(unsigned Count, MVT::ValueType VT, SDOperand Chain,
323 SDOperand Ptr, SDOperand SV);
325 /// getStore - Helper function to build ISD::STORE nodes.
327 SDOperand getStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
328 const Value *SV, int SVOffset, bool isVolatile=false,
329 unsigned Alignment=0);
330 SDOperand getTruncStore(SDOperand Chain, SDOperand Val, SDOperand Ptr,
331 const Value *SV, int SVOffset, MVT::ValueType TVT,
332 bool isVolatile=false, unsigned Alignment=0);
333 SDOperand getIndexedStore(SDOperand OrigStoe, SDOperand Base,
334 SDOperand Offset, ISD::MemIndexedMode AM);
336 // getSrcValue - construct a node to track a Value* through the backend
337 SDOperand getSrcValue(const Value* I, int offset = 0);
339 /// UpdateNodeOperands - *Mutate* the specified node in-place to have the
340 /// specified operands. If the resultant node already exists in the DAG,
341 /// this does not modify the specified node, instead it returns the node that
342 /// already exists. If the resultant node does not exist in the DAG, the
343 /// input node is returned. As a degenerate case, if you specify the same
344 /// input operands as the node already has, the input node is returned.
345 SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op);
346 SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2);
347 SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
349 SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
350 SDOperand Op3, SDOperand Op4);
351 SDOperand UpdateNodeOperands(SDOperand N, SDOperand Op1, SDOperand Op2,
352 SDOperand Op3, SDOperand Op4, SDOperand Op5);
353 SDOperand UpdateNodeOperands(SDOperand N, SDOperand *Ops, unsigned NumOps);
355 /// SelectNodeTo - These are used for target selectors to *mutate* the
356 /// specified node to have the specified return type, Target opcode, and
357 /// operands. Note that target opcodes are stored as
358 /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field. The 0th value
359 /// of the resultant node is returned.
360 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
361 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
363 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
364 SDOperand Op1, SDOperand Op2);
365 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
366 SDOperand Op1, SDOperand Op2, SDOperand Op3);
367 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
368 const SDOperand *Ops, unsigned NumOps);
369 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
370 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
371 SDNode *SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
372 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
376 /// getTargetNode - These are used for target selectors to create a new node
377 /// with specified return type(s), target opcode, and operands.
379 /// Note that getTargetNode returns the resultant node. If there is already a
380 /// node of the specified opcode and operands, it returns that node instead of
382 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT);
383 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
385 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
386 SDOperand Op1, SDOperand Op2);
387 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
388 SDOperand Op1, SDOperand Op2, SDOperand Op3);
389 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT,
390 const SDOperand *Ops, unsigned NumOps);
391 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
392 MVT::ValueType VT2, SDOperand Op1);
393 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
394 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
395 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
396 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
398 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
400 const SDOperand *Ops, unsigned NumOps);
401 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
402 MVT::ValueType VT2, MVT::ValueType VT3,
403 SDOperand Op1, SDOperand Op2);
404 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
405 MVT::ValueType VT2, MVT::ValueType VT3,
406 SDOperand Op1, SDOperand Op2, SDOperand Op3);
407 SDNode *getTargetNode(unsigned Opcode, MVT::ValueType VT1,
408 MVT::ValueType VT2, MVT::ValueType VT3,
409 const SDOperand *Ops, unsigned NumOps);
411 /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
412 /// This can cause recursive merging of nodes in the DAG. Use the first
413 /// version if 'From' is known to have a single result, use the second
414 /// if you have two nodes with identical results, use the third otherwise.
416 /// These methods all take an optional vector, which (if not null) is
417 /// populated with any nodes that are deleted from the SelectionDAG, due to
418 /// new equivalences that are discovered.
420 void ReplaceAllUsesWith(SDOperand From, SDOperand Op,
421 std::vector<SDNode*> *Deleted = 0);
422 void ReplaceAllUsesWith(SDNode *From, SDNode *To,
423 std::vector<SDNode*> *Deleted = 0);
424 void ReplaceAllUsesWith(SDNode *From, const SDOperand *To,
425 std::vector<SDNode*> *Deleted = 0);
427 /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
428 /// uses of other values produced by From.Val alone. The Deleted vector is
429 /// handled the same was as for ReplaceAllUsesWith, but it is required for
431 void ReplaceAllUsesOfValueWith(SDOperand From, SDOperand To,
432 std::vector<SDNode*> &Deleted);
434 /// AssignNodeIds - Assign a unique node id for each node in the DAG based on
435 /// their allnodes order. It returns the maximum id.
436 unsigned AssignNodeIds();
438 /// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
439 /// based on their topological order. It returns the maximum id and a vector
440 /// of the SDNodes* in assigned order by reference.
441 unsigned AssignTopologicalOrder(std::vector<SDNode*> &TopOrder);
443 /// isCommutativeBinOp - Returns true if the opcode is a commutative binary
445 static bool isCommutativeBinOp(unsigned Opcode) {
457 case ISD::ADDE: return true;
458 default: return false;
464 /// FoldSetCC - Constant fold a setcc to true or false.
465 SDOperand FoldSetCC(MVT::ValueType VT, SDOperand N1,
466 SDOperand N2, ISD::CondCode Cond);
469 void RemoveNodeFromCSEMaps(SDNode *N);
470 SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
471 SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op, void *&InsertPos);
472 SDNode *FindModifiedNodeSlot(SDNode *N, SDOperand Op1, SDOperand Op2,
474 SDNode *FindModifiedNodeSlot(SDNode *N, const SDOperand *Ops, unsigned NumOps,
477 void DeleteNodeNotInCSEMaps(SDNode *N);
479 // List of non-single value types.
480 std::list<std::vector<MVT::ValueType> > VTList;
482 // Maps to auto-CSE operations.
483 std::vector<CondCodeSDNode*> CondCodeNodes;
485 std::vector<SDNode*> ValueTypeNodes;
486 std::map<std::string, SDNode*> ExternalSymbols;
487 std::map<std::string, SDNode*> TargetExternalSymbols;
488 std::map<std::string, StringSDNode*> StringNodes;
491 template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
492 typedef SelectionDAG::allnodes_iterator nodes_iterator;
493 static nodes_iterator nodes_begin(SelectionDAG *G) {
494 return G->allnodes_begin();
496 static nodes_iterator nodes_end(SelectionDAG *G) {
497 return G->allnodes_end();
501 } // end namespace llvm