llvm-6502/include/llvm/Analysis/IVUsers.h

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//===- 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/Support/ValueHandle.h"
namespace llvm {
class DominatorTree;
class Instruction;
class Value;
class IVUsers;
class ScalarEvolution;
class SCEV;
/// IVStrideUse - Keep track of one use of a strided induction variable.
/// The Expr member keeps track of the expression, User is the actual user
/// instruction 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(IVUsers *P, const SCEV *S, const SCEV *Off,
Instruction* U, Value *O)
: CallbackVH(U), Parent(P), Stride(S), Offset(Off),
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 IVUsers that owns
/// this IVStrideUse.
IVUsers *getParent() const { return Parent; }
/// getStride - Return the expression for the stride for the use.
const SCEV *getStride() const { return Stride; }
/// setStride - Assign a new stride to this use.
void setStride(const SCEV *Val) {
Stride = Val;
}
/// 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 IVUsers that owns this IVStrideUse.
IVUsers *Parent;
/// Stride - The stride for this use.
const SCEV *Stride;
/// 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;
};
class IVUsers : public LoopPass {
friend class IVStrideUse;
Loop *L;
LoopInfo *LI;
DominatorTree *DT;
ScalarEvolution *SE;
SmallPtrSet<Instruction*,16> Processed;
/// IVUses - A list of all tracked IV uses of induction variable expressions
/// we are interested in.
ilist<IVStrideUse> IVUses;
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);
IVStrideUse &AddUser(const SCEV *Stride, const SCEV *Offset,
Instruction *User, Value *Operand);
/// getReplacementExpr - Return a SCEV expression which computes the
/// value of the OperandValToReplace of the given IVStrideUse.
const SCEV *getReplacementExpr(const IVStrideUse &U) const;
/// getCanonicalExpr - Return a SCEV expression which computes the
/// value of the SCEV of the given IVStrideUse, ignoring the
/// isUseOfPostIncrementedValue flag.
const SCEV *getCanonicalExpr(const IVStrideUse &U) const;
typedef ilist<IVStrideUse>::iterator iterator;
typedef ilist<IVStrideUse>::const_iterator const_iterator;
iterator begin() { return IVUses.begin(); }
iterator end() { return IVUses.end(); }
const_iterator begin() const { return IVUses.begin(); }
const_iterator end() const { return IVUses.end(); }
bool empty() const { return IVUses.empty(); }
void print(raw_ostream &OS, const Module* = 0) const;
/// dump - This method is used for debugging.
void dump() const;
};
Pass *createIVUsersPass();
}
#endif