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 /// Legalize - This transforms the SelectionDAG into a SelectionDAG that is
83 /// compatible with the target instruction selector, as indicated by the
84 /// TargetLowering object.
86 /// Note that this is an involved process that may invalidate pointers into
90 /// RemoveDeadNodes - This method deletes all unreachable nodes in the
91 /// SelectionDAG, including nodes (like loads) that have uses of their token
92 /// chain but no other uses and no side effect. If a node is passed in as an
93 /// argument, it is used as the seed for node deletion.
94 void RemoveDeadNodes(SDNode *N = 0);
96 SDOperand getConstant(uint64_t Val, MVT::ValueType VT);
97 SDOperand getTargetConstant(uint64_t Val, MVT::ValueType VT);
98 SDOperand getConstantFP(double Val, MVT::ValueType VT);
99 SDOperand getGlobalAddress(const GlobalValue *GV, MVT::ValueType VT);
100 SDOperand getTargetGlobalAddress(const GlobalValue *GV, MVT::ValueType VT);
101 SDOperand getFrameIndex(int FI, MVT::ValueType VT);
102 SDOperand getTargetFrameIndex(int FI, MVT::ValueType VT);
103 SDOperand getConstantPool(Constant *C, MVT::ValueType VT);
104 SDOperand getTargetConstantPool(Constant *C, MVT::ValueType VT);
105 SDOperand getBasicBlock(MachineBasicBlock *MBB);
106 SDOperand getExternalSymbol(const char *Sym, MVT::ValueType VT);
107 SDOperand getValueType(MVT::ValueType);
108 SDOperand getRegister(unsigned Reg, MVT::ValueType VT);
110 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N) {
111 return getNode(ISD::CopyToReg, MVT::Other, Chain,
112 getRegister(Reg, N.getValueType()), N);
115 // This version of the getCopyToReg method takes an extra operand, which
116 // indicates that there is potentially an incoming flag value (if Flag is not
117 // null) and that there should be a flag result.
118 SDOperand getCopyToReg(SDOperand Chain, unsigned Reg, SDOperand N,
120 std::vector<MVT::ValueType> VTs;
121 VTs.push_back(MVT::Other);
122 VTs.push_back(MVT::Flag);
123 std::vector<SDOperand> Ops;
124 Ops.push_back(Chain);
125 Ops.push_back(getRegister(Reg, N.getValueType()));
127 if (Flag.Val) Ops.push_back(Flag);
128 return getNode(ISD::CopyToReg, VTs, Ops);
131 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
132 std::vector<MVT::ValueType> ResultTys;
133 ResultTys.push_back(VT);
134 ResultTys.push_back(MVT::Other);
135 std::vector<SDOperand> Ops;
136 Ops.push_back(Chain);
137 Ops.push_back(getRegister(Reg, VT));
138 return getNode(ISD::CopyFromReg, ResultTys, Ops);
141 // This version of the getCopyFromReg method takes an extra operand, which
142 // indicates that there is potentially an incoming flag value (if Flag is not
143 // null) and that there should be a flag result.
144 SDOperand getCopyFromReg(SDOperand Chain, unsigned Reg, MVT::ValueType VT,
146 std::vector<MVT::ValueType> ResultTys;
147 ResultTys.push_back(VT);
148 ResultTys.push_back(MVT::Other);
149 ResultTys.push_back(MVT::Flag);
150 std::vector<SDOperand> Ops;
151 Ops.push_back(Chain);
152 Ops.push_back(getRegister(Reg, VT));
153 if (Flag.Val) Ops.push_back(Flag);
154 return getNode(ISD::CopyFromReg, ResultTys, Ops);
157 SDOperand getImplicitDef(SDOperand Chain, unsigned Reg, MVT::ValueType VT) {
158 return getNode(ISD::ImplicitDef, MVT::Other, Chain, getRegister(Reg, VT));
161 /// getCall - Note that this destroys the vector of RetVals passed in.
163 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
164 SDOperand Callee, bool isTailCall = false) {
165 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, Chain,
167 NN->setValueTypes(RetVals);
168 AllNodes.push_back(NN);
172 /// getCall - This is identical to the one above, and should be used for calls
173 /// where arguments are passed in physical registers. This destroys the
174 /// RetVals and ArgsInRegs vectors.
175 SDNode *getCall(std::vector<MVT::ValueType> &RetVals, SDOperand Chain,
176 SDOperand Callee, std::vector<SDOperand> &ArgsInRegs,
177 bool isTailCall = false) {
178 ArgsInRegs.insert(ArgsInRegs.begin(), Callee);
179 ArgsInRegs.insert(ArgsInRegs.begin(), Chain);
180 SDNode *NN = new SDNode(isTailCall ? ISD::TAILCALL : ISD::CALL, ArgsInRegs);
181 NN->setValueTypes(RetVals);
182 AllNodes.push_back(NN);
186 SDOperand getCondCode(ISD::CondCode Cond);
188 /// getZeroExtendInReg - Return the expression required to zero extend the Op
189 /// value assuming it was the smaller SrcTy value.
190 SDOperand getZeroExtendInReg(SDOperand Op, MVT::ValueType SrcTy);
192 /// getNode - Gets or creates the specified node.
194 SDOperand getNode(unsigned Opcode, MVT::ValueType VT);
195 SDOperand getNode(unsigned Opcode, MVT::ValueType VT, SDOperand N);
196 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
197 SDOperand N1, SDOperand N2);
198 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
199 SDOperand N1, SDOperand N2, SDOperand N3);
200 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
201 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4);
202 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
203 SDOperand N1, SDOperand N2, SDOperand N3, SDOperand N4,
205 SDOperand getNode(unsigned Opcode, MVT::ValueType VT,
206 std::vector<SDOperand> &Children);
207 SDOperand getNode(unsigned Opcode, std::vector<MVT::ValueType> &ResultTys,
208 std::vector<SDOperand> &Ops);
210 /// getSetCC - Helper function to make it easier to build SetCC's if you just
211 /// have an ISD::CondCode instead of an SDOperand.
213 SDOperand getSetCC(MVT::ValueType VT, SDOperand LHS, SDOperand RHS,
214 ISD::CondCode Cond) {
215 return getNode(ISD::SETCC, VT, LHS, RHS, getCondCode(Cond));
218 /// getSelectCC - Helper function to make it easier to build SelectCC's if you
219 /// just have an ISD::CondCode instead of an SDOperand.
221 SDOperand getSelectCC(SDOperand LHS, SDOperand RHS,
222 SDOperand True, SDOperand False, ISD::CondCode Cond) {
223 MVT::ValueType VT = True.getValueType();
224 return getNode(ISD::SELECT_CC, VT, LHS, RHS, True, False,getCondCode(Cond));
227 /// getBR2Way_CC - Helper function to make it easier to build BRTWOWAY_CC
230 SDOperand getBR2Way_CC(SDOperand Chain, SDOperand CCNode, SDOperand LHS,
231 SDOperand RHS, SDOperand True, SDOperand False) {
232 std::vector<SDOperand> Ops;
233 Ops.push_back(Chain);
234 Ops.push_back(CCNode);
238 Ops.push_back(False);
239 return getNode(ISD::BRTWOWAY_CC, MVT::Other, Ops);
242 /// getLoad - Loads are not normal binary operators: their result type is not
243 /// determined by their operands, and they produce a value AND a token chain.
245 SDOperand getLoad(MVT::ValueType VT, SDOperand Chain, SDOperand Ptr,
247 SDOperand getExtLoad(unsigned Opcode, MVT::ValueType VT, SDOperand Chain,
248 SDOperand Ptr, SDOperand SV, MVT::ValueType EVT);
250 // getSrcValue - construct a node to track a Value* through the backend
251 SDOperand getSrcValue(const Value* I, int offset = 0);
254 /// SelectNodeTo - These are used for target selectors to *mutate* the
255 /// specified node to have the specified return type, Target opcode, and
256 /// operands. Note that target opcodes are stored as
257 /// ISD::BUILTIN_OP_END+TargetOpcode in the node opcode field.
258 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT);
259 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
261 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
262 SDOperand Op1, SDOperand Op2);
263 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
264 SDOperand Op1, SDOperand Op2, SDOperand Op3);
265 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
266 SDOperand Op1, SDOperand Op2, SDOperand Op3, SDOperand Op4);
267 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT,
268 SDOperand Op1, SDOperand Op2, SDOperand Op3, SDOperand Op4,
270 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
271 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2);
272 void SelectNodeTo(SDNode *N, unsigned TargetOpc, MVT::ValueType VT1,
273 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2,
276 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
278 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1);
280 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
281 SDOperand Op1, SDOperand Op2) {
282 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2);
284 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT1,
285 MVT::ValueType VT2, SDOperand Op1, SDOperand Op2) {
286 std::vector<MVT::ValueType> ResultTys;
287 ResultTys.push_back(VT1);
288 ResultTys.push_back(VT2);
289 std::vector<SDOperand> Ops;
292 return getNode(ISD::BUILTIN_OP_END+Opcode, ResultTys, Ops);
294 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
295 SDOperand Op1, SDOperand Op2, SDOperand Op3) {
296 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3);
298 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
299 SDOperand Op1, SDOperand Op2, SDOperand Op3,
301 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3, Op4);
303 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
304 SDOperand Op1, SDOperand Op2, SDOperand Op3,
305 SDOperand Op4, SDOperand Op5) {
306 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Op1, Op2, Op3, Op4, Op5);
308 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT,
309 std::vector<SDOperand> &Ops) {
310 return getNode(ISD::BUILTIN_OP_END+Opcode, VT, Ops);
312 SDOperand getTargetNode(unsigned Opcode, MVT::ValueType VT1,
313 MVT::ValueType VT2, std::vector<SDOperand> &Ops) {
314 std::vector<MVT::ValueType> ResultTys;
315 ResultTys.push_back(VT1);
316 ResultTys.push_back(VT2);
317 return getNode(ISD::BUILTIN_OP_END+Opcode, ResultTys, Ops);
320 /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
321 /// This can cause recursive merging of nodes in the DAG. Use the first
322 /// version if 'From' is known to have a single result, use the second
323 /// if you have two nodes with identical results, use the third otherwise.
325 void ReplaceAllUsesWith(SDOperand From, SDOperand Op);
326 void ReplaceAllUsesWith(SDNode *From, SDNode *To);
327 void ReplaceAllUsesWith(SDNode *From, const std::vector<SDOperand> &To);
330 /// DeleteNode - Remove the specified node from the system. This node must
331 /// have no referrers.
332 void DeleteNode(SDNode *N);
337 void RemoveNodeFromCSEMaps(SDNode *N);
338 SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
339 void DeleteNodeIfDead(SDNode *N, void *NodeSet);
341 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
342 /// and cc. If unable to simplify it, return a null SDOperand.
343 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N1,
344 SDOperand N2, ISD::CondCode Cond);
346 /// SimplifySelectCC - Try to simplify a select_cc built with the specified
347 /// operands and cc. This can be used to simplify both the select_cc node,
348 /// and a select node whose first operand is a setcc.
349 SDOperand SimplifySelectCC(SDOperand N1, SDOperand N2, SDOperand N3,
350 SDOperand N4, ISD::CondCode CC);
352 // Maps to auto-CSE operations.
353 std::map<std::pair<unsigned, std::pair<SDOperand, MVT::ValueType> >,
355 std::map<std::pair<unsigned, std::pair<SDOperand, SDOperand> >,
358 std::map<std::pair<unsigned, MVT::ValueType>, RegisterSDNode*> RegNodes;
359 std::vector<CondCodeSDNode*> CondCodeNodes;
361 std::map<std::pair<SDOperand, std::pair<SDOperand, MVT::ValueType> >,
364 std::map<const GlobalValue*, SDNode*> GlobalValues;
365 std::map<const GlobalValue*, SDNode*> TargetGlobalValues;
366 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> Constants;
367 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> TargetConstants;
368 std::map<std::pair<uint64_t, MVT::ValueType>, SDNode*> ConstantFPs;
369 std::map<int, SDNode*> FrameIndices, TargetFrameIndices;
370 std::map<Constant *, SDNode*> ConstantPoolIndices;
371 std::map<Constant *, SDNode*> TargetConstantPoolIndices;
372 std::map<MachineBasicBlock *, SDNode*> BBNodes;
373 std::vector<SDNode*> ValueTypeNodes;
374 std::map<std::string, SDNode*> ExternalSymbols;
375 std::map<std::pair<unsigned,
376 std::pair<MVT::ValueType, std::vector<SDOperand> > >,
377 SDNode*> OneResultNodes;
378 std::map<std::pair<unsigned,
379 std::pair<std::vector<MVT::ValueType>,
380 std::vector<SDOperand> > >,
381 SDNode*> ArbitraryNodes;
384 template <> struct GraphTraits<SelectionDAG*> : public GraphTraits<SDNode*> {
385 typedef SelectionDAG::allnodes_iterator nodes_iterator;
386 static nodes_iterator nodes_begin(SelectionDAG *G) {
387 return G->allnodes_begin();
389 static nodes_iterator nodes_end(SelectionDAG *G) {
390 return G->allnodes_end();