RegAllocPBQP.cpp

  DEBUG(dbgs() << "PBQP Register Allocating for " << mf->getFunction()->getName() << "\n");

  // Allocator main loop:
  //
  // * Map current regalloc problem to a PBQP problem
  // * Solve the PBQP problem
  // * Map the solution back to a register allocation
  // * Spill if necessary
  //
  // This process is continued till no more spills are generated.

  // Find the vreg intervals in need of allocation.
  findVRegIntervalsToAlloc();

  // If there are non-empty intervals allocate them using pbqp.
  if (!vregsToAlloc.empty()) {

    bool pbqpAllocComplete = false;
    unsigned round = 0;

    if (!pbqpBuilder) {
      while (!pbqpAllocComplete) {
        DEBUG(dbgs() << "  PBQP Regalloc round " << round << ":\n");

        PBQP::Graph problem = constructPBQPProblem();
        PBQP::Solution solution =
          PBQP::HeuristicSolver<PBQP::Heuristics::Briggs>::solve(problem);

        pbqpAllocComplete = mapPBQPToRegAlloc(solution);

        ++round;
      }
    } else {
      while (!pbqpAllocComplete) {
        DEBUG(dbgs() << "  PBQP Regalloc round " << round << ":\n");

        std::auto_ptr<PBQPRAProblem> problem =
          builder->build(mf, lis, vregsToAlloc);
        PBQP::Solution solution =
          HeuristicSolver<Briggs>::solve(problem->getGraph());

        pbqpAllocComplete = mapPBQPToRegAlloc2(*problem, solution);

        ++round;
      }
    }
  }

  // Finalise allocation, allocate empty ranges.
  finalizeAlloc();

  rmf->renderMachineFunction("After PBQP register allocation.", vrm);

  vregsToAlloc.clear();
  emptyIntervalVRegs.clear();
  li2Node.clear();
  node2LI.clear();
  allowedSets.clear();
  problemNodes.clear();

  DEBUG(dbgs() << "Post alloc VirtRegMap:\n" << *vrm << "\n");

  // Run rewriter
  std::auto_ptr<VirtRegRewriter> rewriter(createVirtRegRewriter());

  rewriter->runOnMachineFunction(*mf, *vrm, lis);

  return true;
}

FunctionPass* createPBQPRegisterAllocator() {
  return new RegAllocPBQP(std::auto_ptr<PBQPBuilder>(new PBQPBuilder()));
}

}

#undef DEBUG_TYPE