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97f51a3024
methods * Eliminate AnalysisID: Now it is just a typedef for const PassInfo* * Simplify how AnalysisID's are initialized * Eliminate Analysis/Writer.cpp/.h: incorporate printing functionality into the analyses themselves. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3115 91177308-0d34-0410-b5e6-96231b3b80d8
54 lines
2.0 KiB
C++
54 lines
2.0 KiB
C++
//===- llvm/Analysis/InductionVariable.h - Induction variable ----*- C++ -*--=//
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//
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// This interface is used to identify and classify induction variables that
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// exist in the program. Induction variables must contain a PHI node that
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// exists in a loop header. Because of this, they are identified an managed by
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// this PHI node.
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//
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// Induction variables are classified into a type. Knowing that an induction
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// variable is of a specific type can constrain the values of the start and
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// step. For example, a SimpleLinear induction variable must have a start and
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// step values that are constants.
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//
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// Induction variables can be created with or without loop information. If no
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// loop information is available, induction variables cannot be recognized to be
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// more than SimpleLinear variables.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_INDUCTIONVARIABLE_H
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#define LLVM_ANALYSIS_INDUCTIONVARIABLE_H
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#include <iosfwd>
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class Value;
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class PHINode;
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class Instruction;
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class LoopInfo; class Loop;
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class InductionVariable {
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public:
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enum iType { // Identify the type of this induction variable
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Cannonical, // Starts at 0, counts by 1
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SimpleLinear, // Simple linear: Constant start, constant step
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Linear, // General linear: loop invariant start, and step
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Unknown, // Unknown type. Start & Step are null
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} InductionType;
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Value *Start, *Step; // Start and step expressions for this indvar
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PHINode *Phi; // The PHI node that corresponds to this indvar
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public:
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// Create an induction variable for the specified value. If it is a PHI, and
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// if it's recognizable, classify it and fill in instance variables.
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//
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InductionVariable(PHINode *PN, LoopInfo *LoopInfo = 0);
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// Classify Induction
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static enum iType Classify(const Value *Start, const Value *Step,
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const Loop *L = 0);
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void print(std::ostream &OS) const;
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};
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#endif
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