llvm-mirror/include/llvm/Analysis/ScalarEvolutionAliasAnalysis.h

//===- ScalarEvolutionAliasAnalysis.h - SCEV-based AA -----------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This is the interface for a SCEV-based alias analysis.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONALIASANALYSIS_H
#define LLVM_ANALYSIS_SCALAREVOLUTIONALIASANALYSIS_H

#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"

namespace llvm {

/// A simple alias analysis implementation that uses ScalarEvolution to answer
/// queries.
class ScalarEvolutionAliasAnalysis : public FunctionPass, public AliasAnalysis {
  ScalarEvolution *SE;

public:
  static char ID; // Class identification, replacement for typeinfo
  ScalarEvolutionAliasAnalysis() : FunctionPass(ID), SE(nullptr) {
    initializeScalarEvolutionAliasAnalysisPass(
        *PassRegistry::getPassRegistry());
  }

  /// This method is used when a pass implements an analysis interface through
  /// multiple inheritance.
  ///
  /// If needed, it should override this to adjust the this pointer as needed
  /// for the specified pass info.
  void *getAdjustedAnalysisPointer(AnalysisID PI) override {
    if (PI == &AliasAnalysis::ID)
      return (AliasAnalysis *)this;
    return this;
  }

private:
  void getAnalysisUsage(AnalysisUsage &AU) const override;
  bool runOnFunction(Function &F) override;
  AliasResult alias(const MemoryLocation &LocA,
                    const MemoryLocation &LocB) override;

  Value *GetBaseValue(const SCEV *S);
};

/// Creates an instance of \c ScalarEvolutionAliasAnalysis.
FunctionPass *createScalarEvolutionAliasAnalysisPass();

}

#endif