//===------ DeLICM.cpp -----------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Undo the effect of Loop Invariant Code Motion (LICM) and
// GVN Partial Redundancy Elimination (PRE) on SCoP-level.
//
// Namely, remove register/scalar dependencies by mapping them back to array
// elements.
//
//===----------------------------------------------------------------------===//

#include "polly/DeLICM.h"
#include "polly/ScopInfo.h"
#include "polly/ScopPass.h"
#define DEBUG_TYPE "polly-delicm"

using namespace polly;
using namespace llvm;

namespace {

class DeLICM : public ScopPass {
private:
  DeLICM(const DeLICM &) = delete;
  const DeLICM &operator=(const DeLICM &) = delete;

public:
  static char ID;
  explicit DeLICM() : ScopPass(ID) {}

  virtual void getAnalysisUsage(AnalysisUsage &AU) const override {
    AU.addRequiredTransitive<ScopInfoRegionPass>();
    AU.setPreservesAll();
  }

  virtual bool runOnScop(Scop &S) override {
    // Free resources for previous scop's computation, if not yet done.
    releaseMemory();

    // TODO: Run DeLICM algorithm

    return false;
  }

  virtual void printScop(raw_ostream &OS, Scop &S) const override {
    OS << "DeLICM result:\n";
    // TODO: Print analysis results and performed transformation details
  }

  virtual void releaseMemory() override {
    // TODO: Release resources (eg. shared_ptr to isl_ctx)
  }
};

char DeLICM::ID;
} // anonymous namespace

Pass *polly::createDeLICMPass() { return new DeLICM(); }

INITIALIZE_PASS_BEGIN(DeLICM, "polly-delicm", "Polly - DeLICM/DePRE", false,
                      false)
INITIALIZE_PASS_DEPENDENCY(ScopInfoWrapperPass)
INITIALIZE_PASS_END(DeLICM, "polly-delicm", "Polly - DeLICM/DePRE", false,
                    false)