ScalarEvolutionExpander.h revision 9c9fcfc719158a46cb2e41b66d7dc1a63cd48d74
15f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)//===---- llvm/Analysis/ScalarEvolutionExpander.h - SCEV Exprs --*- C++ -*-===// 25f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// 35f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// The LLVM Compiler Infrastructure 45f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// 55f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// This file is distributed under the University of Illinois Open Source 65f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// License. See LICENSE.TXT for details. 75f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// 85f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)//===----------------------------------------------------------------------===// 95f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// 105f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// This file defines the classes used to generate code from scalar expressions. 115f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// 125f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)//===----------------------------------------------------------------------===// 135f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 145f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H 155f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H 165f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 175f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include "llvm/Analysis/ScalarEvolutionExpressions.h" 185f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include "llvm/Analysis/ScalarEvolutionNormalization.h" 195f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include "llvm/Support/IRBuilder.h" 205f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include "llvm/Support/TargetFolder.h" 215f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include "llvm/Support/ValueHandle.h" 225f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)#include <set> 235f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 245f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)namespace llvm { 255f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// SCEVExpander - This class uses information about analyze scalars to 265f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// rewrite expressions in canonical form. 275f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// 285f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// Clients should create an instance of this class when rewriting is needed, 295f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// and destroy it when finished to allow the release of the associated 305f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// memory. 315f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) class SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> { 325f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) ScalarEvolution &SE; 335f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> > 345f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) InsertedExpressions; 355f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) std::set<AssertingVH<Value> > InsertedValues; 365f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) std::set<AssertingVH<Value> > InsertedPostIncValues; 375f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 385f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// RelevantLoops - A memoization of the "relevant" loop for a given SCEV. 395f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) DenseMap<const SCEV *, const Loop *> RelevantLoops; 405f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 415f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// PostIncLoops - Addrecs referring to any of the given loops are expanded 425f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// in post-inc mode. For example, expanding {1,+,1}<L> in post-inc mode 435f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// returns the add instruction that adds one to the phi for {0,+,1}<L>, 445f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// as opposed to a new phi starting at 1. This is only supported in 455f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// non-canonical mode. 465f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) PostIncLoopSet PostIncLoops; 475f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 485f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// IVIncInsertPos - When this is non-null, addrecs expanded in the 495f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// loop it indicates should be inserted with increments at 505f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// IVIncInsertPos. 515f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) const Loop *IVIncInsertLoop; 525f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 535f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// IVIncInsertPos - When expanding addrecs in the IVIncInsertLoop loop, 545f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// insert the IV increment at this position. 555f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Instruction *IVIncInsertPos; 565f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 575f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// CanonicalMode - When true, expressions are expanded in "canonical" 585f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// form. In particular, addrecs are expanded as arithmetic based on 595f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// a canonical induction variable. When false, expression are expanded 605f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// in a more literal form. 615f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) bool CanonicalMode; 625f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 635f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) typedef IRBuilder<true, TargetFolder> BuilderType; 645f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) BuilderType Builder; 655f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 665f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) friend struct SCEVVisitor<SCEVExpander, Value*>; 675f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 685f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) public: 695f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// SCEVExpander - Construct a SCEVExpander in "canonical" mode. 705f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) explicit SCEVExpander(ScalarEvolution &se) 715f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) : SE(se), IVIncInsertLoop(0), CanonicalMode(true), 725f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Builder(se.getContext(), TargetFolder(se.TD)) {} 735f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 745f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// clear - Erase the contents of the InsertedExpressions map so that users 755f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// trying to expand the same expression into multiple BasicBlocks or 765f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// different places within the same BasicBlock can do so. 775f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void clear() { 785f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) InsertedExpressions.clear(); 795f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) InsertedValues.clear(); 805f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) InsertedPostIncValues.clear(); 815f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) } 825f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 835f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// getOrInsertCanonicalInductionVariable - This method returns the 845f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// canonical induction variable of the specified type for the specified 855f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// loop (inserting one if there is none). A canonical induction variable 865f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// starts at zero and steps by one on each iteration. 875f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) PHINode *getOrInsertCanonicalInductionVariable(const Loop *L, 885f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) const Type *Ty); 895f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 905f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// expandCodeFor - Insert code to directly compute the specified SCEV 915f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// expression into the program. The inserted code is inserted into the 925f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// specified block. 935f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Value *expandCodeFor(const SCEV *SH, const Type *Ty, Instruction *I); 945f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 955f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// setIVIncInsertPos - Set the current IV increment loop and position. 965f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void setIVIncInsertPos(const Loop *L, Instruction *Pos) { 975f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) assert(!CanonicalMode && 985f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) "IV increment positions are not supported in CanonicalMode"); 995f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) IVIncInsertLoop = L; 1005f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) IVIncInsertPos = Pos; 1015f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) } 1025f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1035f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// setPostInc - Enable post-inc expansion for addrecs referring to the 1045f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// given loops. Post-inc expansion is only supported in non-canonical 1055f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// mode. 1065f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void setPostInc(const PostIncLoopSet &L) { 1075f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) assert(!CanonicalMode && 1085f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) "Post-inc expansion is not supported in CanonicalMode"); 1095f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) PostIncLoops = L; 1105f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) } 1115f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1125f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// clearPostInc - Disable all post-inc expansion. 1135f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void clearPostInc() { 1145f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) PostIncLoops.clear(); 1155f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1165f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) // When we change the post-inc loop set, cached expansions may no 1175f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) // longer be valid. 1185f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) InsertedPostIncValues.clear(); 1195f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) } 1205f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1215f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// disableCanonicalMode - Disable the behavior of expanding expressions in 1225f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// canonical form rather than in a more literal form. Non-canonical mode 1235f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// is useful for late optimization passes. 1245f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void disableCanonicalMode() { CanonicalMode = false; } 1255f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1265f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// clearInsertPoint - Clear the current insertion point. This is useful 1275f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// if the instruction that had been serving as the insertion point may 1285f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// have been deleted. 1295f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) void clearInsertPoint() { 1305f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Builder.ClearInsertionPoint(); 1315f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) } 1325f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1335f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) private: 1345f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) LLVMContext &getContext() const { return SE.getContext(); } 1355f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1365f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// InsertBinop - Insert the specified binary operator, doing a small amount 1375f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// of work to avoid inserting an obviously redundant operation. 1385f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS); 1395f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 1405f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// ReuseOrCreateCast - Arange for there to be a cast of V to Ty at IP, 1415f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// reusing an existing cast if a suitable one exists, moving an existing 1425f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// cast if a suitable one exists but isn't in the right place, or 1435f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) /// or creating a new one. 1445f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Value *ReuseOrCreateCast(Value *V, const Type *Ty, 1455f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) Instruction::CastOps Op, 1465f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) BasicBlock::iterator IP); 147 148 /// InsertNoopCastOfTo - Insert a cast of V to the specified type, 149 /// which must be possible with a noop cast, doing what we can to 150 /// share the casts. 151 Value *InsertNoopCastOfTo(Value *V, const Type *Ty); 152 153 /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP 154 /// instead of using ptrtoint+arithmetic+inttoptr. 155 Value *expandAddToGEP(const SCEV *const *op_begin, 156 const SCEV *const *op_end, 157 const PointerType *PTy, const Type *Ty, Value *V); 158 159 Value *expand(const SCEV *S); 160 161 /// expandCodeFor - Insert code to directly compute the specified SCEV 162 /// expression into the program. The inserted code is inserted into the 163 /// SCEVExpander's current insertion point. If a type is specified, the 164 /// result will be expanded to have that type, with a cast if necessary. 165 Value *expandCodeFor(const SCEV *SH, const Type *Ty = 0); 166 167 /// isInsertedInstruction - Return true if the specified instruction was 168 /// inserted by the code rewriter. If so, the client should not modify the 169 /// instruction. 170 bool isInsertedInstruction(Instruction *I) const { 171 return InsertedValues.count(I) || InsertedPostIncValues.count(I); 172 } 173 174 /// getRelevantLoop - Determine the most "relevant" loop for the given SCEV. 175 const Loop *getRelevantLoop(const SCEV *); 176 177 Value *visitConstant(const SCEVConstant *S) { 178 return S->getValue(); 179 } 180 181 Value *visitTruncateExpr(const SCEVTruncateExpr *S); 182 183 Value *visitZeroExtendExpr(const SCEVZeroExtendExpr *S); 184 185 Value *visitSignExtendExpr(const SCEVSignExtendExpr *S); 186 187 Value *visitAddExpr(const SCEVAddExpr *S); 188 189 Value *visitMulExpr(const SCEVMulExpr *S); 190 191 Value *visitUDivExpr(const SCEVUDivExpr *S); 192 193 Value *visitAddRecExpr(const SCEVAddRecExpr *S); 194 195 Value *visitSMaxExpr(const SCEVSMaxExpr *S); 196 197 Value *visitUMaxExpr(const SCEVUMaxExpr *S); 198 199 Value *visitUnknown(const SCEVUnknown *S) { 200 return S->getValue(); 201 } 202 203 void rememberInstruction(Value *I); 204 205 void restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I); 206 207 Value *expandAddRecExprLiterally(const SCEVAddRecExpr *); 208 PHINode *getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized, 209 const Loop *L, 210 const Type *ExpandTy, 211 const Type *IntTy); 212 }; 213} 214 215#endif 216