| //===- llvm/Analysis/IVUsers.h - Induction Variable Users -------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements bookkeeping for "interesting" users of expressions |
| // computed from induction variables. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ANALYSIS_IVUSERS_H |
| #define LLVM_ANALYSIS_IVUSERS_H |
| |
| #include "llvm/Analysis/LoopPass.h" |
| #include "llvm/Analysis/ScalarEvolution.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include <map> |
| |
| namespace llvm { |
| |
| class DominatorTree; |
| class Instruction; |
| class Value; |
| struct IVUsersOfOneStride; |
| |
| /// IVStrideUse - Keep track of one use of a strided induction variable, where |
| /// the stride is stored externally. The Offset member keeps track of the |
| /// offset from the IV, User is the actual user of the operand, and |
| /// 'OperandValToReplace' is the operand of the User that is the use. |
| class IVStrideUse : public CallbackVH, public ilist_node<IVStrideUse> { |
| public: |
| IVStrideUse(IVUsersOfOneStride *parent, |
| const SCEV *offset, |
| Instruction* U, Value *O) |
| : CallbackVH(U), Parent(parent), Offset(offset), |
| OperandValToReplace(O), |
| IsUseOfPostIncrementedValue(false) { |
| } |
| |
| /// getUser - Return the user instruction for this use. |
| Instruction *getUser() const { |
| return cast<Instruction>(getValPtr()); |
| } |
| |
| /// setUser - Assign a new user instruction for this use. |
| void setUser(Instruction *NewUser) { |
| setValPtr(NewUser); |
| } |
| |
| /// getParent - Return a pointer to the IVUsersOfOneStride that owns |
| /// this IVStrideUse. |
| IVUsersOfOneStride *getParent() const { return Parent; } |
| |
| /// getOffset - Return the offset to add to a theoeretical induction |
| /// variable that starts at zero and counts up by the stride to compute |
| /// the value for the use. This always has the same type as the stride. |
| const SCEV *getOffset() const { return Offset; } |
| |
| /// setOffset - Assign a new offset to this use. |
| void setOffset(const SCEV *Val) { |
| Offset = Val; |
| } |
| |
| /// getOperandValToReplace - Return the Value of the operand in the user |
| /// instruction that this IVStrideUse is representing. |
| Value *getOperandValToReplace() const { |
| return OperandValToReplace; |
| } |
| |
| /// setOperandValToReplace - Assign a new Value as the operand value |
| /// to replace. |
| void setOperandValToReplace(Value *Op) { |
| OperandValToReplace = Op; |
| } |
| |
| /// isUseOfPostIncrementedValue - True if this should use the |
| /// post-incremented version of this IV, not the preincremented version. |
| /// This can only be set in special cases, such as the terminating setcc |
| /// instruction for a loop or uses dominated by the loop. |
| bool isUseOfPostIncrementedValue() const { |
| return IsUseOfPostIncrementedValue; |
| } |
| |
| /// setIsUseOfPostIncrmentedValue - set the flag that indicates whether |
| /// this is a post-increment use. |
| void setIsUseOfPostIncrementedValue(bool Val) { |
| IsUseOfPostIncrementedValue = Val; |
| } |
| |
| private: |
| /// Parent - a pointer to the IVUsersOfOneStride that owns this IVStrideUse. |
| IVUsersOfOneStride *Parent; |
| |
| /// Offset - The offset to add to the base induction expression. |
| const SCEV *Offset; |
| |
| /// OperandValToReplace - The Value of the operand in the user instruction |
| /// that this IVStrideUse is representing. |
| WeakVH OperandValToReplace; |
| |
| /// IsUseOfPostIncrementedValue - True if this should use the |
| /// post-incremented version of this IV, not the preincremented version. |
| bool IsUseOfPostIncrementedValue; |
| |
| /// Deleted - Implementation of CallbackVH virtual function to |
| /// recieve notification when the User is deleted. |
| virtual void deleted(); |
| }; |
| |
| template<> struct ilist_traits<IVStrideUse> |
| : public ilist_default_traits<IVStrideUse> { |
| // createSentinel is used to get hold of a node that marks the end of |
| // the list... |
| // The sentinel is relative to this instance, so we use a non-static |
| // method. |
| IVStrideUse *createSentinel() const { |
| // since i(p)lists always publicly derive from the corresponding |
| // traits, placing a data member in this class will augment i(p)list. |
| // But since the NodeTy is expected to publicly derive from |
| // ilist_node<NodeTy>, there is a legal viable downcast from it |
| // to NodeTy. We use this trick to superpose i(p)list with a "ghostly" |
| // NodeTy, which becomes the sentinel. Dereferencing the sentinel is |
| // forbidden (save the ilist_node<NodeTy>) so no one will ever notice |
| // the superposition. |
| return static_cast<IVStrideUse*>(&Sentinel); |
| } |
| static void destroySentinel(IVStrideUse*) {} |
| |
| IVStrideUse *provideInitialHead() const { return createSentinel(); } |
| IVStrideUse *ensureHead(IVStrideUse*) const { return createSentinel(); } |
| static void noteHead(IVStrideUse*, IVStrideUse*) {} |
| |
| private: |
| mutable ilist_node<IVStrideUse> Sentinel; |
| }; |
| |
| /// IVUsersOfOneStride - This structure keeps track of all instructions that |
| /// have an operand that is based on the trip count multiplied by some stride. |
| struct IVUsersOfOneStride : public ilist_node<IVUsersOfOneStride> { |
| private: |
| IVUsersOfOneStride(const IVUsersOfOneStride &I); // do not implement |
| void operator=(const IVUsersOfOneStride &I); // do not implement |
| |
| public: |
| IVUsersOfOneStride() : Stride(0) {} |
| |
| explicit IVUsersOfOneStride(const SCEV *stride) : Stride(stride) {} |
| |
| /// Stride - The stride for all the contained IVStrideUses. This is |
| /// a constant for affine strides. |
| const SCEV *Stride; |
| |
| /// Users - Keep track of all of the users of this stride as well as the |
| /// initial value and the operand that uses the IV. |
| ilist<IVStrideUse> Users; |
| |
| void addUser(const SCEV *Offset, Instruction *User, Value *Operand) { |
| Users.push_back(new IVStrideUse(this, Offset, User, Operand)); |
| } |
| }; |
| |
| class IVUsers : public LoopPass { |
| friend class IVStrideUserVH; |
| Loop *L; |
| LoopInfo *LI; |
| DominatorTree *DT; |
| ScalarEvolution *SE; |
| SmallPtrSet<Instruction*,16> Processed; |
| |
| public: |
| /// IVUses - A list of all tracked IV uses of induction variable expressions |
| /// we are interested in. |
| ilist<IVUsersOfOneStride> IVUses; |
| |
| /// IVUsesByStride - A mapping from the strides in StrideOrder to the |
| /// uses in IVUses. |
| std::map<const SCEV *, IVUsersOfOneStride*> IVUsesByStride; |
| |
| /// StrideOrder - An ordering of the keys in IVUsesByStride that is stable: |
| /// We use this to iterate over the IVUsesByStride collection without being |
| /// dependent on random ordering of pointers in the process. |
| SmallVector<const SCEV *, 16> StrideOrder; |
| |
| private: |
| virtual void getAnalysisUsage(AnalysisUsage &AU) const; |
| |
| virtual bool runOnLoop(Loop *L, LPPassManager &LPM); |
| |
| virtual void releaseMemory(); |
| |
| public: |
| static char ID; // Pass ID, replacement for typeid |
| IVUsers(); |
| |
| /// AddUsersIfInteresting - Inspect the specified Instruction. If it is a |
| /// reducible SCEV, recursively add its users to the IVUsesByStride set and |
| /// return true. Otherwise, return false. |
| bool AddUsersIfInteresting(Instruction *I); |
| |
| /// getReplacementExpr - Return a SCEV expression which computes the |
| /// value of the OperandValToReplace of the given IVStrideUse. |
| const SCEV *getReplacementExpr(const IVStrideUse &U) const; |
| |
| void print(raw_ostream &OS, const Module* = 0) const; |
| virtual void print(std::ostream &OS, const Module* = 0) const; |
| void print(std::ostream *OS, const Module* M = 0) const { |
| if (OS) print(*OS, M); |
| } |
| |
| /// dump - This method is used for debugging. |
| void dump() const; |
| }; |
| |
| Pass *createIVUsersPass(); |
| |
| } |
| |
| #endif |