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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73906 91177308-0d34-0410-b5e6-96231b3b80d8
223 lines
7.6 KiB
C++
223 lines
7.6 KiB
C++
//===- llvm/Analysis/IVUsers.h - Induction Variable Users -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements bookkeeping for "interesting" users of expressions
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// computed from induction variables.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_IVUSERS_H
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#define LLVM_ANALYSIS_IVUSERS_H
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#include "llvm/Analysis/LoopPass.h"
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#include "llvm/Analysis/ScalarEvolution.h"
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#include <llvm/ADT/SmallVector.h>
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#include <map>
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namespace llvm {
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class DominatorTree;
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class Instruction;
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class Value;
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class IVUsersOfOneStride;
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/// IVStrideUse - Keep track of one use of a strided induction variable, where
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/// the stride is stored externally. The Offset member keeps track of the
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/// offset from the IV, User is the actual user of the operand, and
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/// 'OperandValToReplace' is the operand of the User that is the use.
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class IVStrideUse : public CallbackVH, public ilist_node<IVStrideUse> {
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public:
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IVStrideUse(IVUsersOfOneStride *parent,
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const SCEV* offset,
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Instruction* U, Value *O)
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: CallbackVH(U), Parent(parent), Offset(offset),
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OperandValToReplace(O),
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IsUseOfPostIncrementedValue(false) {
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}
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/// getUser - Return the user instruction for this use.
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Instruction *getUser() const {
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return cast<Instruction>(getValPtr());
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}
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/// setUser - Assign a new user instruction for this use.
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void setUser(Instruction *NewUser) {
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setValPtr(NewUser);
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}
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/// getParent - Return a pointer to the IVUsersOfOneStride that owns
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/// this IVStrideUse.
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IVUsersOfOneStride *getParent() const { return Parent; }
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/// getOffset - Return the offset to add to a theoeretical induction
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/// variable that starts at zero and counts up by the stride to compute
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/// the value for the use. This always has the same type as the stride.
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const SCEV* getOffset() const { return Offset; }
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/// setOffset - Assign a new offset to this use.
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void setOffset(const SCEV* Val) {
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Offset = Val;
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}
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/// getOperandValToReplace - Return the Value of the operand in the user
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/// instruction that this IVStrideUse is representing.
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Value *getOperandValToReplace() const {
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return OperandValToReplace;
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}
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/// setOperandValToReplace - Assign a new Value as the operand value
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/// to replace.
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void setOperandValToReplace(Value *Op) {
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OperandValToReplace = Op;
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}
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/// isUseOfPostIncrementedValue - True if this should use the
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/// post-incremented version of this IV, not the preincremented version.
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/// This can only be set in special cases, such as the terminating setcc
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/// instruction for a loop or uses dominated by the loop.
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bool isUseOfPostIncrementedValue() const {
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return IsUseOfPostIncrementedValue;
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}
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/// setIsUseOfPostIncrmentedValue - set the flag that indicates whether
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/// this is a post-increment use.
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void setIsUseOfPostIncrementedValue(bool Val) {
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IsUseOfPostIncrementedValue = Val;
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}
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private:
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/// Parent - a pointer to the IVUsersOfOneStride that owns this IVStrideUse.
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IVUsersOfOneStride *Parent;
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/// Offset - The offset to add to the base induction expression.
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const SCEV* Offset;
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/// OperandValToReplace - The Value of the operand in the user instruction
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/// that this IVStrideUse is representing.
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WeakVH OperandValToReplace;
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/// IsUseOfPostIncrementedValue - True if this should use the
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/// post-incremented version of this IV, not the preincremented version.
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bool IsUseOfPostIncrementedValue;
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/// Deleted - Implementation of CallbackVH virtual function to
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/// recieve notification when the User is deleted.
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virtual void deleted();
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};
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template<> struct ilist_traits<IVStrideUse>
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: public ilist_default_traits<IVStrideUse> {
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// createSentinel is used to get hold of a node that marks the end of
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// the list...
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// The sentinel is relative to this instance, so we use a non-static
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// method.
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IVStrideUse *createSentinel() const {
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// since i(p)lists always publicly derive from the corresponding
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// traits, placing a data member in this class will augment i(p)list.
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// But since the NodeTy is expected to publicly derive from
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// ilist_node<NodeTy>, there is a legal viable downcast from it
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// to NodeTy. We use this trick to superpose i(p)list with a "ghostly"
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// NodeTy, which becomes the sentinel. Dereferencing the sentinel is
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// forbidden (save the ilist_node<NodeTy>) so no one will ever notice
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// the superposition.
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return static_cast<IVStrideUse*>(&Sentinel);
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}
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static void destroySentinel(IVStrideUse*) {}
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IVStrideUse *provideInitialHead() const { return createSentinel(); }
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IVStrideUse *ensureHead(IVStrideUse*) const { return createSentinel(); }
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static void noteHead(IVStrideUse*, IVStrideUse*) {}
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private:
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mutable ilist_node<IVStrideUse> Sentinel;
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};
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/// IVUsersOfOneStride - This structure keeps track of all instructions that
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/// have an operand that is based on the trip count multiplied by some stride.
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struct IVUsersOfOneStride : public ilist_node<IVUsersOfOneStride> {
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private:
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IVUsersOfOneStride(const IVUsersOfOneStride &I); // do not implement
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void operator=(const IVUsersOfOneStride &I); // do not implement
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public:
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IVUsersOfOneStride() : Stride(0) {}
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explicit IVUsersOfOneStride(const SCEV *stride) : Stride(stride) {}
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/// Stride - The stride for all the contained IVStrideUses. This is
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/// a constant for affine strides.
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const SCEV *Stride;
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/// Users - Keep track of all of the users of this stride as well as the
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/// initial value and the operand that uses the IV.
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ilist<IVStrideUse> Users;
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void addUser(const SCEV* Offset, Instruction *User, Value *Operand) {
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Users.push_back(new IVStrideUse(this, Offset, User, Operand));
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}
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};
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class IVUsers : public LoopPass {
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friend class IVStrideUserVH;
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Loop *L;
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LoopInfo *LI;
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DominatorTree *DT;
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ScalarEvolution *SE;
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SmallPtrSet<Instruction*,16> Processed;
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public:
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/// IVUses - A list of all tracked IV uses of induction variable expressions
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/// we are interested in.
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ilist<IVUsersOfOneStride> IVUses;
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/// IVUsesByStride - A mapping from the strides in StrideOrder to the
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/// uses in IVUses.
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std::map<const SCEV*, IVUsersOfOneStride*> IVUsesByStride;
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/// StrideOrder - An ordering of the keys in IVUsesByStride that is stable:
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/// We use this to iterate over the IVUsesByStride collection without being
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/// dependent on random ordering of pointers in the process.
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SmallVector<const SCEV*, 16> StrideOrder;
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private:
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virtual void getAnalysisUsage(AnalysisUsage &AU) const;
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virtual bool runOnLoop(Loop *L, LPPassManager &LPM);
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virtual void releaseMemory();
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public:
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static char ID; // Pass ID, replacement for typeid
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IVUsers();
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/// AddUsersIfInteresting - Inspect the specified Instruction. If it is a
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/// reducible SCEV, recursively add its users to the IVUsesByStride set and
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/// return true. Otherwise, return false.
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bool AddUsersIfInteresting(Instruction *I);
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/// getReplacementExpr - Return a SCEV expression which computes the
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/// value of the OperandValToReplace of the given IVStrideUse.
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const SCEV* getReplacementExpr(const IVStrideUse &U) const;
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void print(raw_ostream &OS, const Module* = 0) const;
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virtual void print(std::ostream &OS, const Module* = 0) const;
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void print(std::ostream *OS, const Module* M = 0) const {
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if (OS) print(*OS, M);
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}
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/// dump - This method is used for debugging.
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void dump() const;
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};
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Pass *createIVUsersPass();
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}
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#endif
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