예제 #1
0
// Compare VirtRegMap::getRegAllocPref().
AllocationOrder::AllocationOrder(unsigned VirtReg,
                                 const VirtRegMap &VRM,
                                 const BitVector &ReservedRegs)
  : Pos(0), Reserved(ReservedRegs) {
  const TargetRegisterClass *RC = VRM.getRegInfo().getRegClass(VirtReg);
  std::pair<unsigned, unsigned> HintPair =
    VRM.getRegInfo().getRegAllocationHint(VirtReg);

  // HintPair.second is a register, phys or virt.
  Hint = HintPair.second;

  // Translate to physreg, or 0 if not assigned yet.
  if (TargetRegisterInfo::isVirtualRegister(Hint))
    Hint = VRM.getPhys(Hint);

  // The remaining allocation order may depend on the hint.
  tie(Begin, End) = VRM.getTargetRegInfo()
        .getAllocationOrder(RC, HintPair.first, Hint, VRM.getMachineFunction());

  // Target-dependent hints require resolution.
  if (HintPair.first)
    Hint = VRM.getTargetRegInfo().ResolveRegAllocHint(HintPair.first, Hint,
                                                      VRM.getMachineFunction());

  // The hint must be a valid physreg for allocation.
  if (Hint && (!TargetRegisterInfo::isPhysicalRegister(Hint) ||
               !RC->contains(Hint) || ReservedRegs.test(Hint)))
    Hint = 0;
}
예제 #2
0
void RegAllocBase::init(VirtRegMap &vrm,
                        LiveIntervals &lis,
                        LiveRegMatrix &mat) {
  TRI = &vrm.getTargetRegInfo();
  MRI = &vrm.getRegInfo();
  VRM = &vrm;
  LIS = &lis;
  Matrix = &mat;
  MRI->freezeReservedRegs(vrm.getMachineFunction());
  RegClassInfo.runOnMachineFunction(vrm.getMachineFunction());
}
예제 #3
0
void RegAllocBase::init(VirtRegMap &vrm, LiveIntervals &lis) {
  NamedRegionTimer T("Initialize", TimerGroupName, TimePassesIsEnabled);
  TRI = &vrm.getTargetRegInfo();
  MRI = &vrm.getRegInfo();
  VRM = &vrm;
  LIS = &lis;
  RegClassInfo.runOnMachineFunction(vrm.getMachineFunction());

  const unsigned NumRegs = TRI->getNumRegs();
  if (NumRegs != PhysReg2LiveUnion.numRegs()) {
    PhysReg2LiveUnion.init(UnionAllocator, NumRegs);
    // Cache an interferece query for each physical reg
    Queries.reset(new LiveIntervalUnion::Query[PhysReg2LiveUnion.numRegs()]);
  }
}
예제 #4
0
void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
                                      LiveIntervals &LIS, VirtRegMap &VRM,
                                      const TargetInstrInfo &TII) {
  SetVector<LiveInterval*,
            SmallVector<LiveInterval*, 8>,
            SmallPtrSet<LiveInterval*, 8> > ToShrink;
  MachineRegisterInfo &MRI = VRM.getRegInfo();

  for (;;) {
    // Erase all dead defs.
    while (!Dead.empty()) {
      MachineInstr *MI = Dead.pop_back_val();
      assert(MI->allDefsAreDead() && "Def isn't really dead");
      SlotIndex Idx = LIS.getInstructionIndex(MI).getDefIndex();

      // Never delete inline asm.
      if (MI->isInlineAsm()) {
        DEBUG(dbgs() << "Won't delete: " << Idx << '\t' << *MI);
        continue;
      }

      // Use the same criteria as DeadMachineInstructionElim.
      bool SawStore = false;
      if (!MI->isSafeToMove(&TII, 0, SawStore)) {
        DEBUG(dbgs() << "Can't delete: " << Idx << '\t' << *MI);
        continue;
      }

      DEBUG(dbgs() << "Deleting dead def " << Idx << '\t' << *MI);

      // Check for live intervals that may shrink
      for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
             MOE = MI->operands_end(); MOI != MOE; ++MOI) {
        if (!MOI->isReg())
          continue;
        unsigned Reg = MOI->getReg();
        if (!TargetRegisterInfo::isVirtualRegister(Reg))
          continue;
        LiveInterval &LI = LIS.getInterval(Reg);

        // Shrink read registers, unless it is likely to be expensive and
        // unlikely to change anything. We typically don't want to shrink the
        // PIC base register that has lots of uses everywhere.
        // Always shrink COPY uses that probably come from live range splitting.
        if (MI->readsVirtualRegister(Reg) &&
            (MI->isCopy() || MOI->isDef() || MRI.hasOneNonDBGUse(Reg) ||
             LI.killedAt(Idx)))
          ToShrink.insert(&LI);

        // Remove defined value.
        if (MOI->isDef()) {
          if (VNInfo *VNI = LI.getVNInfoAt(Idx)) {
            if (delegate_)
              delegate_->LRE_WillShrinkVirtReg(LI.reg);
            LI.removeValNo(VNI);
            if (LI.empty()) {
              ToShrink.remove(&LI);
              eraseVirtReg(Reg, LIS);
            }
          }
        }
      }

      if (delegate_)
        delegate_->LRE_WillEraseInstruction(MI);
      LIS.RemoveMachineInstrFromMaps(MI);
      MI->eraseFromParent();
      ++NumDCEDeleted;
    }

    if (ToShrink.empty())
      break;

    // Shrink just one live interval. Then delete new dead defs.
    LiveInterval *LI = ToShrink.back();
    ToShrink.pop_back();
    if (foldAsLoad(LI, Dead, MRI, LIS, TII))
      continue;
    if (delegate_)
      delegate_->LRE_WillShrinkVirtReg(LI->reg);
    if (!LIS.shrinkToUses(LI, &Dead))
      continue;

    // LI may have been separated, create new intervals.
    LI->RenumberValues(LIS);
    ConnectedVNInfoEqClasses ConEQ(LIS);
    unsigned NumComp = ConEQ.Classify(LI);
    if (NumComp <= 1)
      continue;
    ++NumFracRanges;
    bool IsOriginal = VRM.getOriginal(LI->reg) == LI->reg;
    DEBUG(dbgs() << NumComp << " components: " << *LI << '\n');
    SmallVector<LiveInterval*, 8> Dups(1, LI);
    for (unsigned i = 1; i != NumComp; ++i) {
      Dups.push_back(&createFrom(LI->reg, LIS, VRM));
      // If LI is an original interval that hasn't been split yet, make the new
      // intervals their own originals instead of referring to LI. The original
      // interval must contain all the split products, and LI doesn't.
      if (IsOriginal)
        VRM.setIsSplitFromReg(Dups.back()->reg, 0);
      if (delegate_)
        delegate_->LRE_DidCloneVirtReg(Dups.back()->reg, LI->reg);
    }
    ConEQ.Distribute(&Dups[0], MRI);
  }
}