ScalarEvolutionExpander.h revision 9269926bfb713e92e328e9578c6d8826c68dcb9d
136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===---- llvm/Analysis/ScalarEvolutionExpander.h - SCEV Exprs --*- C++ -*-===// 236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// The LLVM Compiler Infrastructure 436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 57ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// This file is distributed under the University of Illinois Open Source 67ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// License. See LICENSE.TXT for details. 736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===----------------------------------------------------------------------===// 936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 1036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// This file defines the classes used to generate code from scalar expressions. 1136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman// 1236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman//===----------------------------------------------------------------------===// 1336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 1436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman#ifndef LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H 1536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman#define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H 1636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 1736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman#include "llvm/Analysis/ScalarEvolutionExpressions.h" 18267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman#include "llvm/Support/IRBuilder.h" 19267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman#include "llvm/Support/TargetFolder.h" 2003ee68a145ab5394c070298049d93f305be93ec3Dan Gohman#include <set> 2136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 2236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begemannamespace llvm { 2336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// SCEVExpander - This class uses information about analyze scalars to 2436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// rewrite expressions in canonical form. 2536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// 2636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// Clients should create an instance of this class when rewriting is needed, 274c0d5d5db876b0628bdf6a2174263a1c0a9130e2Dan Gohman /// and destroy it when finished to allow the release of the associated 2836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// memory. 29a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman class SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> { 3036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman ScalarEvolution &SE; 31667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> > 32667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman InsertedExpressions; 3399a1302ae4c438ab532826685280c0b69687e163Dan Gohman std::set<Value*> InsertedValues; 3436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 35a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// PostIncLoop - When non-null, expanded addrecs referring to the given 36a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// loop expanded in post-inc mode. For example, expanding {1,+,1}<L> in 37a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// post-inc mode returns the add instruction that adds one to the phi 38a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// for {0,+,1}<L>, as opposed to a new phi starting at 1. This is only 39a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// supported in non-canonical mode. 40a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman const Loop *PostIncLoop; 41a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 42a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// IVIncInsertPos - When this is non-null, addrecs expanded in the 43a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// loop it indicates should be inserted with increments at 44a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// IVIncInsertPos. 45a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman const Loop *IVIncInsertLoop; 46a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 47a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// IVIncInsertPos - When expanding addrecs in the IVIncInsertLoop loop, 48a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// insert the IV increment at this position. 49a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman Instruction *IVIncInsertPos; 50a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 51a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// CanonicalMode - When true, expressions are expanded in "canonical" 52a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// form. In particular, addrecs are expanded as arithmetic based on 53a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// a canonical induction variable. When false, expression are expanded 54a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// in a more literal form. 55a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman bool CanonicalMode; 56a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 57267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman typedef IRBuilder<true, TargetFolder> BuilderType; 58267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman BuilderType Builder; 5936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 6036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman friend struct SCEVVisitor<SCEVExpander, Value*>; 619269926bfb713e92e328e9578c6d8826c68dcb9dDan Gohman 6236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman public: 63a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// SCEVExpander - Construct a SCEVExpander in "canonical" mode. 645be18e84766fb495b0bde3c8244c1df459a18683Dan Gohman explicit SCEVExpander(ScalarEvolution &se) 65a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman : SE(se), PostIncLoop(0), IVIncInsertLoop(0), CanonicalMode(true), 66a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman Builder(se.getContext(), TargetFolder(se.TD)) {} 678f9f0d3a34ebbcd6d075fbb1250dc74f36579d50Chris Lattner 6836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// clear - Erase the contents of the InsertedExpressions map so that users 69d29b6aa608d69f19b57ebd2ae630b040b1c4951dJeff Cohen /// trying to expand the same expression into multiple BasicBlocks or 7036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// different places within the same BasicBlock can do so. 7136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman void clear() { InsertedExpressions.clear(); } 72d29b6aa608d69f19b57ebd2ae630b040b1c4951dJeff Cohen 7336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// getOrInsertCanonicalInductionVariable - This method returns the 7436f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// canonical induction variable of the specified type for the specified 7536f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// loop (inserting one if there is none). A canonical induction variable 7636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// starts at zero and steps by one on each iteration. 771d09de3eca23267855e28297fcb40de3632ea47bDan Gohman Value *getOrInsertCanonicalInductionVariable(const Loop *L, const Type *Ty); 7836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 79752ec7da506f5d41c08bd37e195750b57550ce68Dan Gohman /// expandCodeFor - Insert code to directly compute the specified SCEV 80752ec7da506f5d41c08bd37e195750b57550ce68Dan Gohman /// expression into the program. The inserted code is inserted into the 8136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman /// specified block. 82a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman Value *expandCodeFor(const SCEV *SH, const Type *Ty, Instruction *I) { 83a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman BasicBlock::iterator IP = I; 84a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman while (isInsertedInstruction(IP)) ++IP; 85267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman Builder.SetInsertPoint(IP->getParent(), IP); 86752ec7da506f5d41c08bd37e195750b57550ce68Dan Gohman return expandCodeFor(SH, Ty); 87752ec7da506f5d41c08bd37e195750b57550ce68Dan Gohman } 8836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 89a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// setIVIncInsertPos - Set the current IV increment loop and position. 90a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman void setIVIncInsertPos(const Loop *L, Instruction *Pos) { 91a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman assert(!CanonicalMode && 92a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman "IV increment positions are not supported in CanonicalMode"); 93a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman IVIncInsertLoop = L; 94a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman IVIncInsertPos = Pos; 95a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman } 96a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 97a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// setPostInc - If L is non-null, enable post-inc expansion for addrecs 98a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// referring to the given loop. If L is null, disable post-inc expansion 99a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// completely. Post-inc expansion is only supported in non-canonical 100a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// mode. 101a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman void setPostInc(const Loop *L) { 102a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman assert(!CanonicalMode && 103a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman "Post-inc expansion is not supported in CanonicalMode"); 104a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman PostIncLoop = L; 105a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman } 106a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 107a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// disableCanonicalMode - Disable the behavior of expanding expressions in 108a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// canonical form rather than in a more literal form. Non-canonical mode 109a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman /// is useful for late optimization passes. 110a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman void disableCanonicalMode() { CanonicalMode = false; } 111a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 112267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman private: 113e922c0201916e0b980ab3cfe91e1413e68d55647Owen Anderson LLVMContext &getContext() const { return SE.getContext(); } 1144c0d5d5db876b0628bdf6a2174263a1c0a9130e2Dan Gohman 115267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman /// InsertBinop - Insert the specified binary operator, doing a small amount 116267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman /// of work to avoid inserting an obviously redundant operation. 117267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS); 118af79fb5f47b0088c6a8973a7fdbaea96973a429dDan Gohman 119af79fb5f47b0088c6a8973a7fdbaea96973a429dDan Gohman /// InsertNoopCastOfTo - Insert a cast of V to the specified type, 120267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman /// which must be possible with a noop cast, doing what we can to 121267a385342f2e7388f178b327dd87c5f29afd51bDan Gohman /// share the casts. 122af79fb5f47b0088c6a8973a7fdbaea96973a429dDan Gohman Value *InsertNoopCastOfTo(Value *V, const Type *Ty); 123af79fb5f47b0088c6a8973a7fdbaea96973a429dDan Gohman 1245be18e84766fb495b0bde3c8244c1df459a18683Dan Gohman /// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP 1255be18e84766fb495b0bde3c8244c1df459a18683Dan Gohman /// instead of using ptrtoint+arithmetic+inttoptr. 1260bba49cebc50c7bd4662a4807bcb3ee7f42cb470Dan Gohman Value *expandAddToGEP(const SCEV *const *op_begin, 1270bba49cebc50c7bd4662a4807bcb3ee7f42cb470Dan Gohman const SCEV *const *op_end, 128453aa4fbf1083cc7f646a0ac21e2bcc384a91ae9Dan Gohman const PointerType *PTy, const Type *Ty, Value *V); 1295be18e84766fb495b0bde3c8244c1df459a18683Dan Gohman 130890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *expand(const SCEV *S); 1312d1be87ee40a4a0241d94448173879d9df2bc5b3Dan Gohman 132667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// expandCodeFor - Insert code to directly compute the specified SCEV 133667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// expression into the program. The inserted code is inserted into the 134667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// SCEVExpander's current insertion point. If a type is specified, the 135667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// result will be expanded to have that type, with a cast if necessary. 1360bba49cebc50c7bd4662a4807bcb3ee7f42cb470Dan Gohman Value *expandCodeFor(const SCEV *SH, const Type *Ty = 0); 137667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman 138667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// isInsertedInstruction - Return true if the specified instruction was 139667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// inserted by the code rewriter. If so, the client should not modify the 140667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman /// instruction. 141667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman bool isInsertedInstruction(Instruction *I) const { 142667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman return InsertedValues.count(I); 143667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman } 144667d787c0a21cf3f5dfcde03ca471162ba35b614Dan Gohman 145890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitConstant(const SCEVConstant *S) { 14636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman return S->getValue(); 14736f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman } 14836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 149890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitTruncateExpr(const SCEVTruncateExpr *S); 15036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 151890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitZeroExtendExpr(const SCEVZeroExtendExpr *S); 15236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 153890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitSignExtendExpr(const SCEVSignExtendExpr *S); 154d19534add90a2a894af61523b830887097bb780bDan Gohman 155890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitAddExpr(const SCEVAddExpr *S); 15636f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 157890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitMulExpr(const SCEVMulExpr *S); 15836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 159890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitUDivExpr(const SCEVUDivExpr *S); 16036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 161890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitAddRecExpr(const SCEVAddRecExpr *S); 16236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 163890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitSMaxExpr(const SCEVSMaxExpr *S); 164c54c561c9f7270c055dd7ba75a3a003b771a42d9Nick Lewycky 165890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitUMaxExpr(const SCEVUMaxExpr *S); 1663e6307698084e7adfc10b739442ae29742beefd0Nick Lewycky 167890f92b744fb074465bc2b7006ee753a181f62a4Dan Gohman Value *visitUnknown(const SCEVUnknown *S) { 16836f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman return S->getValue(); 16936f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman } 170a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 171a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman void rememberInstruction(Value *I) { 172a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman if (!PostIncLoop) InsertedValues.insert(I); 173a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman } 174a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman 175a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman Value *expandAddRecExprLiterally(const SCEVAddRecExpr *); 176a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman PHINode *getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized, 177a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman const Loop *L, 178a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman const Type *ExpandTy, 179a10756ee657a4d43a48cca5c166919093930ed6bDan Gohman const Type *IntTy); 18036f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman }; 18136f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman} 18236f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman 18336f891bdf6cf38fcc655a0930ca18664e18518d4Nate Begeman#endif 184