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/CodeGen/SelectionDAGNodes.h"
20 #include <string> // FIXME remove eventually, turning map into const char* map.
25 class MachineFunction;
27 /// SelectionDAG class - This is used to represent a portion of an LLVM function
28 /// in a low-level Data Dependence DAG representation suitable for instruction
29 /// selection. This DAG is constructed as the first step of instruction
30 /// selection in order to allow implementation of machine specific optimizations
31 /// and code simplifications.
33 /// The representation used by the SelectionDAG is a target-independent
34 /// representation, which has some similarities to the GCC RTL representation,
35 /// but is significantly more simple, powerful, and is a graph form instead of a
42 // Root - The root of the entire DAG. EntryNode - The starting token.
43 SDOperand Root, EntryNode;
45 // AllNodes - All of the nodes in the DAG
46 std::vector<SDNode*> AllNodes;
48 // ValueNodes - track SrcValue nodes
49 std::map<std::pair<const Value*, int>, SDNode*> ValueNodes;
52 SelectionDAG(TargetLowering &tli, MachineFunction &mf) : TLI(tli), MF(mf) {
53 EntryNode = Root = getNode(ISD::EntryToken, MVT::Other);
57 MachineFunction &getMachineFunction() const { return MF; }
58 const TargetMachine &getTarget() const;
59 TargetLowering &getTargetLoweringInfo() const { return TLI; }
61 /// viewGraph - Pop up a ghostview window with the DAG rendered using 'dot'.
66 typedef std::vector<SDNode*>::const_iterator allnodes_iterator;
67 allnodes_iterator allnodes_begin() const { return AllNodes.begin(); }
68 allnodes_iterator allnodes_end() const { return AllNodes.end(); }
70 /// getRoot - Return the root tag of the SelectionDAG.
72 const SDOperand &getRoot() const { return Root; }
74 /// getEntryNode - Return the token chain corresponding to the entry of the
76 const SDOperand &getEntryNode() const { return EntryNode; }
78 /// setRoot - Set the current root tag of the SelectionDAG.
80 const SDOperand &setRoot(SDOperand N) { return Root = N; }
82 /// Combine - This iterates over the nodes in the SelectionDAG, folding
83 /// certain types of nodes together, or eliminating superfluous nodes. When
84 /// the AfterLegalize argument is set to 'true', Combine takes care not to
85 /// generate any nodes that will be illegal on the target.
86 void Combine(bool AfterLegalize);
88 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
89 /// compatible with the target instruction selector, as indicated by the
90 /// TargetLowering object.
92 /// Note that this is an involved process that may invalidate pointers into
96 /// RemoveDeadNodes - This method deletes all unreachable nodes in the
97 /// SelectionDAG, including nodes (like loads) that have uses of their token
98 /// chain but no other uses and no side effect. If a node is passed in as an
99 /// argument, it is used as the seed for node deletion.
100 void RemoveDeadNodes(SDNode *N = 0);
102 SDOperand getConstant(uint64_t Val, MVT::ValueType VT);
103 SDOperand getTargetConstant(uint64_t Val, MVT::ValueType VT);
104 SDOperand getConstantFP(double Val, MVT::ValueType VT);
105 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT);
106 SDOperand getTargetGlobalAddress(const GlobalValue *GV, MVT::ValueType VT);
107 SDOperand getFrameIndex(int FI, MVT::ValueType VT);
108 SDOperand getTargetFrameIndex(int FI, MVT::ValueType VT);
109 SDOperand getConstantPool(Constant *C, MVT::ValueType VT);
110 SDOperand getTargetConstantPool(Constant *C, MVT::ValueType VT);
111 SDOperand getBasicBlock(MachineBasicBlock *MBB);
112 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
113 SDOperand getValueType(MVT::ValueType);
114 SDOperand getRegister(unsigned Reg, MVT::ValueType VT);
116 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N) {
117 return getNode(ISD::CopyToReg, MVT::Other, Chain,
118 getRegister(Reg, N.getValueType()), N);
121 // This version of the getCopyToReg method takes an extra operand, which
122 // indicates that there is potentially an incoming flag value (if Flag is not
123 // null) and that there should be a flag result.
124 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N,
126 std::vector<MVT::ValueType> VTs;
127 VTs.push_back(MVT::Other);
128 VTs.push_back(MVT::Flag);
129 std::vector<SDOperand> Ops;
130 Ops.push_back(Chain);
131 Ops.push_back(getRegister(Reg, N.getValueType()));
133 if (Flag.Val) Ops.push_back(Flag);
134 return getNode(ISD::CopyToReg, VTs, Ops);
137 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
138 std::vector<MVT::ValueType> ResultTys;
139 ResultTys.push_back(VT);
140 ResultTys.push_back(MVT::Other);
141 std::vector<SDOperand> Ops;
142 Ops.push_back(Chain);
143 Ops.push_back(getRegister(Reg, VT));
144 return getNode(ISD::CopyFromReg, ResultTys, Ops);
147 // This version of the getCopyFromReg method takes an extra operand, which
148 // indicates that there is potentially an incoming flag value (if Flag is not
149 // null) and that there should be a flag result.
150 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT,
152 std::vector<MVT::ValueType> ResultTys;
153 ResultTys.push_back(VT);
154 ResultTys.push_back(MVT::Other);
155 ResultTys.push_back(MVT::Flag);
156 std::vector<SDOperand> Ops;
157 Ops.push_back(Chain);
158 Ops.push_back(getRegister(Reg, VT));
159 if (Flag.Val) Ops.push_back(Flag);
160 return getNode(ISD::CopyFromReg, ResultTys, Ops);
163 SDOperand getImplicitDef(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
164 return getNode(ISD::ImplicitDef, MVT::Other, Chain, getRegister(Reg, VT));
167 /// getCall - Note that this destroys the vector of RetVals passed in.
169 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
170 SDOperand Callee, bool isTailCall = false) {
171 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, Chain,
173 NN->setValueTypes(RetVals);
174 AllNodes.push_back(NN);
178 /// getCall - This is identical to the one above, and should be used for calls
179 /// where arguments are passed in physical registers. This destroys the
180 /// RetVals and ArgsInRegs vectors.
181 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
182 SDOperand Callee, std::vector<SDOperand> &ArgsInRegs,
183 bool isTailCall = false) {
184 ArgsInRegs.insert(ArgsInRegs.begin(), Callee);
185 ArgsInRegs.insert(ArgsInRegs.begin(), Chain);
186 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, ArgsInRegs);
187 NN->setValueTypes(RetVals);
188 AllNodes.push_back(NN);
192 SDOperand getCondCode(ISD::CondCode Cond);
194 /// getZeroExtendInReg - Return the expression required to zero extend the Op
195 /// value assuming it was the smaller SrcTy value.
196 SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
198 /// getNode - Gets or creates the specified node.
200 SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
201 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
202 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
203 SDOperand N1, SDOperand N2);
204 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
205 SDOperand N1, SDOperand N2, SDOperand N3);
206 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
207 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
208 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
209 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
211 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
212 std::vector<SDOperand> &Children);
213 SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
214 std::vector<SDOperand> &Ops);
216 /// getSetCC - Helper function to make it easier to build SetCC's if you just
217 /// have an ISD::CondCode instead of an SDOperand.
219 SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
220 ISD::CondCode Cond) {
221 return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
224 /// getSelectCC - Helper function to make it easier to build SelectCC's if you
225 /// just have an ISD::CondCode instead of an SDOperand.
227 SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
228 SDOperand True, SDOperand False, ISD::CondCode Cond) {
229 MVT::ValueType VT = True.getValueType();
230 return getNode(ISD::SELECT_CC, VT, LHS, RHS, True, False,getCondCode(Cond));
233 /// getBR2Way_CC - Helper function to make it easier to build BRTWOWAY_CC
236 SDOperand getBR2Way_CC(SDOperand Chain, SDOperand CCNode, SDOperand LHS,
237 SDOperand RHS, SDOperand True, SDOperand False) {
238 std::vector<SDOperand> Ops;
239 Ops.push_back(Chain);
240 Ops.push_back(CCNode);
244 Ops.push_back(False);
245 return getNode(ISD::BRTWOWAY_CC, MVT::Other, Ops);
248 /// getLoad - Loads are not normal binary operators: their result type is not
249 /// determined by their operands, and they produce a value AND a token chain.
251 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
253 SDOperand getExtLoad(unsigned Opcode, MVT::ValueType VT, SDOperand Chain,
254 SDOperand Ptr, SDOperand SV, MVT::ValueType EVT);
256 // getSrcValue - construct a node to track a Value* through the backend
257 SDOperand getSrcValue(const Value* I, int offset = 0);
260 /// SelectNodeTo - These are used for target selectors to *mutate* the
261 /// specified node to have the specified return type, Target opcode, and
262 /// operands. Note that target opcodes are stored as
263 /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field.
264 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
265 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
267 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
268 SDOperand Op1, SDOperand Op2);
269 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
270 SDOperand Op1, SDOperand Op2, SDOperand Op3);
271 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
272 SDOperand Op1, SDOperand Op2, SDOperand Op3, SDOperand Op4);
273 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
274 SDOperand Op1, SDOperand Op2, SDOperand Op3, SDOperand Op4,
276 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
277 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
278 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
279 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
282 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
284 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1);
286 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
287 SDOperand Op1, SDOperand Op2) {
288 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2);
290 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT1,
291 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2) {
292 std::vector<MVT::ValueType> ResultTys;
293 ResultTys.push_back(VT1);
294 ResultTys.push_back(VT2);
295 std::vector<SDOperand> Ops;
298 return getNode(ISD::BUILTIN_OP_END+Opcode, ResultTys, Ops);
300 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
301 SDOperand Op1, SDOperand Op2, SDOperand Op3) {
302 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3);
304 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
305 SDOperand Op1, SDOperand Op2, SDOperand Op3,
307 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3, Op4);
309 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
310 SDOperand Op1, SDOperand Op2, SDOperand Op3,
311 SDOperand Op4, SDOperand Op5) {
312 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3, Op4, Op5);
314 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
315 std::vector<SDOperand> &Ops) {
316 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Ops);
318 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT1,
319 MVT::ValueType VT2, std::vector<SDOperand> &Ops) {
320 std::vector<MVT::ValueType> ResultTys;
321 ResultTys.push_back(VT1);
322 ResultTys.push_back(VT2);
323 return getNode(ISD::BUILTIN_OP_END+Opcode, ResultTys, Ops);
326 /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
327 /// This can cause recursive merging of nodes in the DAG. Use the first
328 /// version if 'From' is known to have a single result, use the second
329 /// if you have two nodes with identical results, use the third otherwise.
331 void ReplaceAllUsesWith(SDOperand From, SDOperand Op);
332 void ReplaceAllUsesWith(SDNode *From, SDNode *To);
333 void ReplaceAllUsesWith(SDNode *From, const std::vector<SDOperand> &To);
336 /// DeleteNode - Remove the specified node from the system. This node must
337 /// have no referrers.
338 void DeleteNode(SDNode *N);
343 void RemoveNodeFromCSEMaps(SDNode *N);
344 SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
345 void DeleteNodeIfDead(SDNode *N, void *NodeSet);
347 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
348 /// and cc. If unable to simplify it, return a null SDOperand.
349 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N1,
350 SDOperand N2, ISD::CondCode Cond);
352 /// SimplifySelectCC - Try to simplify a select_cc built with the specified
353 /// operands and cc. This can be used to simplify both the select_cc node,
354 /// and a select node whose first operand is a setcc.
355 SDOperand SimplifySelectCC(SDOperand N1, SDOperand N2, SDOperand N3,
356 SDOperand N4, ISD::CondCode CC);
358 // Maps to auto-CSE operations.
359 std::map<std::pair<unsigned, MVT::ValueType>, SDNode *> NullaryOps;
360 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >,
362 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >,
365 std::map<std::pair<unsigned, MVT::ValueType>, RegisterSDNode*> RegNodes;
366 std::vector<CondCodeSDNode*> CondCodeNodes;
368 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >,
371 std::map<const GlobalValue*, SDNode*> GlobalValues;
372 std::map<const GlobalValue*, SDNode*> TargetGlobalValues;
373 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants;
374 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> TargetConstants;
375 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> ConstantFPs;
376 std::map<int, SDNode*> FrameIndices, TargetFrameIndices;
377 std::map<Constant *, SDNode*> ConstantPoolIndices;
378 std::map<Constant *, SDNode*> TargetConstantPoolIndices;
379 std::map<MachineBasicBlock *, SDNode*> BBNodes;
380 std::vector<SDNode*> ValueTypeNodes;
381 std::map<std::string, SDNode*> ExternalSymbols;
382 std::map<std::pair<unsigned,
383 std::pair<MVT::ValueType, std::vector<SDOperand> > >,
384 SDNode*> OneResultNodes;
385 std::map<std::pair<unsigned,
386 std::pair<std::vector<MVT::ValueType>,
387 std::vector<SDOperand> > >,
388 SDNode*> ArbitraryNodes;
391 template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
392 typedef SelectionDAG::allnodes_iterator nodes_iterator;
393 static nodes_iterator nodes_begin(SelectionDAG *G) {
394 return G->allnodes_begin();
396 static nodes_iterator nodes_end(SelectionDAG *G) {
397 return G->allnodes_end();