RegisterPressure: A utility for computing register pressure within a

MachineInstr sequence.

This uses the new target interface for tracking register pressure
using pressure sets to model overlapping register classes and
subregisters.

RegisterPressure results can be tracked incrementally or stored at
region boundaries. Global register pressure can be deduced from local
RegisterPressure results if desired.

This is an early, somewhat untested implementation. I'm working on
testing it within the context of a register pressure reducing
MachineScheduler.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155454 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 543 insertions, 0 deletions

diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
new file mode 100644
index 0000000000..7c8f20fb05
--- /dev/null
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -0,0 +1,543 @@
+//===-- RegisterPressure.cpp - Dynamic Register Pressure ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the RegisterPressure class which can be used to track
+// MachineInstr level register pressure.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RegisterClassInfo.h"
+#include "RegisterPressure.h"
+#include "llvm/CodeGen/LiveInterval.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetMachine.h"
+
+using namespace llvm;
+
+/// Increase register pressure for each set impacted by this register class.
+static void increaseSetPressure(std::vector<unsigned> &CurrSetPressure,
+                                std::vector<unsigned> &MaxSetPressure,
+                                const TargetRegisterClass *RC,
+                                const TargetRegisterInfo *TRI) {
+  unsigned Weight = TRI->getRegClassWeight(RC).RegWeight;
+  for (const int *PSet = TRI->getRegClassPressureSets(RC);
+       *PSet != -1; ++PSet) {
+    CurrSetPressure[*PSet] += Weight;
+    if (CurrSetPressure[*PSet] > MaxSetPressure[*PSet])
+      MaxSetPressure[*PSet] = CurrSetPressure[*PSet];
+  }
+}
+
+/// Decrease register pressure for each set impacted by this register class.
+static void decreaseSetPressure(std::vector<unsigned> &CurrSetPressure,
+                                const TargetRegisterClass *RC,
+                                const TargetRegisterInfo *TRI) {
+  unsigned Weight = TRI->getRegClassWeight(RC).RegWeight;
+  for (const int *PSet = TRI->getRegClassPressureSets(RC);
+       *PSet != -1; ++PSet) {
+    assert(CurrSetPressure[*PSet] >= Weight && "register pressure underflow");
+    CurrSetPressure[*PSet] -= Weight;
+  }
+}
+
+/// Directly increase pressure only within this RegisterPressure result.
+void RegisterPressure::increase(const TargetRegisterClass *RC,
+                                const TargetRegisterInfo *TRI) {
+  increaseSetPressure(MaxSetPressure, MaxSetPressure, RC, TRI);
+}
+
+/// Directly decrease pressure only within this RegisterPressure result.
+void RegisterPressure::decrease(const TargetRegisterClass *RC,
+                                const TargetRegisterInfo *TRI) {
+  decreaseSetPressure(MaxSetPressure, RC, TRI);
+}
+
+/// Increase the current pressure as impacted by this physical register and bump
+/// the high water mark if needed.
+void RegPressureTracker::increasePhysRegPressure(unsigned Reg) {
+  increaseSetPressure(CurrSetPressure, P.MaxSetPressure,
+                      TRI->getMinimalPhysRegClass(Reg), TRI);
+}
+
+/// Simply decrease the current pressure as impacted by this physcial register.
+void RegPressureTracker::decreasePhysRegPressure(unsigned Reg) {
+  decreaseSetPressure(CurrSetPressure, TRI->getMinimalPhysRegClass(Reg), TRI);
+}
+
+/// Increase the current pressure as impacted by this virtual register and bump
+/// the high water mark if needed.
+void RegPressureTracker::increaseVirtRegPressure(unsigned Reg) {
+  increaseSetPressure(CurrSetPressure, P.MaxSetPressure,
+                      MRI->getRegClass(Reg), TRI);
+}
+
+/// Simply decrease the current pressure as impacted by this virtual register.
+void RegPressureTracker::decreaseVirtRegPressure(unsigned Reg) {
+  decreaseSetPressure(CurrSetPressure, MRI->getRegClass(Reg), TRI);
+}
+
+/// Clear the result so it can be used for another round of pressure tracking.
+void IntervalPressure::reset() {
+  TopIdx = BottomIdx = SlotIndex();
+  MaxSetPressure.clear();
+  LiveInRegs.clear();
+  LiveOutRegs.clear();
+}
+
+/// Clear the result so it can be used for another round of pressure tracking.
+void RegionPressure::reset() {
+  TopPos = BottomPos = MachineBasicBlock::const_iterator();
+  MaxSetPressure.clear();
+  LiveInRegs.clear();
+  LiveOutRegs.clear();
+}
+
+/// If the current top is not less than or equal to the next index, open it.
+/// We happen to need the SlotIndex for the next top for pressure update.
+void IntervalPressure::openTop(SlotIndex NextTop) {
+  if (TopIdx <= NextTop)
+    return;
+  TopIdx = SlotIndex();
+  LiveInRegs.clear();
+}
+
+/// If the current top is the previous instruction (before receding), open it.
+void RegionPressure::openTop(MachineBasicBlock::const_iterator PrevTop) {
+  if (TopPos != PrevTop)
+    return;
+  TopPos = MachineBasicBlock::const_iterator();
+  LiveInRegs.clear();
+}
+
+/// If the current bottom is not greater than the previous index, open it.
+void IntervalPressure::openBottom(SlotIndex PrevBottom) {
+  if (BottomIdx > PrevBottom)
+    return;
+  BottomIdx = SlotIndex();
+  LiveInRegs.clear();
+}
+
+/// If the current bottom is the previous instr (before advancing), open it.
+void RegionPressure::openBottom(MachineBasicBlock::const_iterator PrevBottom) {
+  if (BottomPos != PrevBottom)
+    return;
+  BottomPos = MachineBasicBlock::const_iterator();
+  LiveInRegs.clear();
+}
+
+/// Setup the RegPressureTracker.
+///
+/// TODO: Add support for pressure without LiveIntervals.
+void RegPressureTracker::init(const MachineFunction *mf,
+                              const RegisterClassInfo *rci,
+                              const LiveIntervals *lis,
+                              const MachineBasicBlock *mbb,
+                              MachineBasicBlock::const_iterator pos)
+{
+  MF = mf;
+  TRI = MF->getTarget().getRegisterInfo();
+  RCI = rci;
+  MRI = &MF->getRegInfo();
+  MBB = mbb;
+
+  if (RequireIntervals) {
+    assert(lis && "IntervalPressure requires LiveIntervals");
+    LIS = lis;
+  }
+
+  CurrPos = pos;
+  while (CurrPos != MBB->end() && CurrPos->isDebugValue())
+    ++CurrPos;
+
+  CurrSetPressure.assign(TRI->getNumRegPressureSets(), 0);
+
+  if (RequireIntervals)
+    static_cast<IntervalPressure&>(P).reset();
+  else
+    static_cast<RegionPressure&>(P).reset();
+  P.MaxSetPressure = CurrSetPressure;
+
+  LivePhysRegs.clear();
+  LivePhysRegs.setUniverse(TRI->getNumRegs());
+  LiveVirtRegs.clear();
+  LiveVirtRegs.setUniverse(MRI->getNumVirtRegs());
+}
+
+/// Does this pressure result have a valid top position and live ins.
+bool RegPressureTracker::isTopClosed() const {
+  if (RequireIntervals)
+    return static_cast<IntervalPressure&>(P).TopIdx.isValid();
+  return (static_cast<RegionPressure&>(P).TopPos ==
+          MachineBasicBlock::const_iterator());
+}
+
+/// Does this pressure result have a valid bottom position and live outs.
+bool RegPressureTracker::isBottomClosed() const {
+  if (RequireIntervals)
+    return static_cast<IntervalPressure&>(P).BottomIdx.isValid();
+  return (static_cast<RegionPressure&>(P).BottomPos ==
+          MachineBasicBlock::const_iterator());
+}
+
+/// Set the boundary for the top of the region and summarize live ins.
+void RegPressureTracker::closeTop() {
+  if (RequireIntervals)
+    static_cast<IntervalPressure&>(P).TopIdx =
+      LIS->getInstructionIndex(CurrPos).getRegSlot();
+  else
+    static_cast<RegionPressure&>(P).TopPos = CurrPos;
+
+  assert(P.LiveInRegs.empty() && "inconsistent max pressure result");
+  P.LiveInRegs.reserve(LivePhysRegs.size() + LiveVirtRegs.size());
+  P.LiveInRegs.append(LivePhysRegs.begin(), LivePhysRegs.end());
+  for (SparseSet<unsigned>::const_iterator I =
+         LiveVirtRegs.begin(), E = LiveVirtRegs.end(); I != E; ++I)
+    P.LiveInRegs.push_back(*I);
+  std::sort(P.LiveInRegs.begin(), P.LiveInRegs.end());
+  P.LiveInRegs.erase(std::unique(P.LiveInRegs.begin(), P.LiveInRegs.end()),
+                     P.LiveInRegs.end());
+}
+
+/// Set the boundary for the bottom of the region and summarize live outs.
+void RegPressureTracker::closeBottom() {
+  if (RequireIntervals)
+    if (CurrPos == MBB->end())
+      static_cast<IntervalPressure&>(P).BottomIdx = LIS->getMBBEndIdx(MBB);
+    else
+      static_cast<IntervalPressure&>(P).BottomIdx =
+        LIS->getInstructionIndex(CurrPos).getRegSlot();
+  else
+    static_cast<RegionPressure&>(P).BottomPos = CurrPos;
+
+  assert(P.LiveOutRegs.empty() && "inconsistent max pressure result");
+  P.LiveOutRegs.reserve(LivePhysRegs.size() + LiveVirtRegs.size());
+  P.LiveOutRegs.append(LivePhysRegs.begin(), LivePhysRegs.end());
+  for (SparseSet<unsigned>::const_iterator I =
+         LiveVirtRegs.begin(), E = LiveVirtRegs.end(); I != E; ++I)
+    P.LiveOutRegs.push_back(*I);
+  std::sort(P.LiveOutRegs.begin(), P.LiveOutRegs.end());
+  P.LiveOutRegs.erase(std::unique(P.LiveOutRegs.begin(), P.LiveOutRegs.end()),
+                      P.LiveOutRegs.end());
+}
+
+/// Finalize the region boundaries and record live ins and live outs.
+void RegPressureTracker::closeRegion() {
+  if (!isTopClosed() && !isBottomClosed()) {
+    assert(LivePhysRegs.empty() && LiveVirtRegs.empty() &&
+           "no region boundary");
+    return;
+  }
+  if (!isBottomClosed())
+    closeBottom();
+  else if (!isTopClosed())
+    closeTop();
+  // If both top and bottom are closed, do nothing.
+}
+
+/// Return true if Reg aliases a register in Regs SparseSet.
+static bool hasRegAlias(unsigned Reg, SparseSet<unsigned> &Regs,
+                        const TargetRegisterInfo *TRI) {
+  assert(!TargetRegisterInfo::isVirtualRegister(Reg) && "only for physregs");
+  for (const uint16_t *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) {
+    if (Regs.count(*Alias))
+      return true;
+  }
+  return false;
+}
+
+/// Return true if Reg aliases a register in unsorted Regs SmallVector.
+/// This is only valid for physical registers.
+static SmallVectorImpl<unsigned>::iterator
+findRegAlias(unsigned Reg, SmallVectorImpl<unsigned> &Regs,
+             const TargetRegisterInfo *TRI) {
+  for (const uint16_t *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) {
+    SmallVectorImpl<unsigned>::iterator I =
+      std::find(Regs.begin(), Regs.end(), *Alias);
+    if (I != Regs.end())
+      return I;
+  }
+  return Regs.end();
+}
+
+/// Return true if Reg can be inserted into Regs SmallVector. For virtual
+/// register, do a linear search. For physical registers check for aliases.
+static SmallVectorImpl<unsigned>::iterator
+findReg(unsigned Reg, bool isVReg, SmallVectorImpl<unsigned> &Regs,
+        const TargetRegisterInfo *TRI) {
+  if(isVReg)
+    return std::find(Regs.begin(), Regs.end(), Reg);
+  return findRegAlias(Reg, Regs, TRI);
+}
+
+/// Collect this instruction's unique uses and defs into SmallVectors for
+/// processing defs and uses in order.
+template<bool isVReg>
+struct RegisterOperands {
+  SmallVector<unsigned, 8> Uses;
+  SmallVector<unsigned, 8> Defs;
+  SmallVector<unsigned, 8> DeadDefs;
+
+  /// Push this operand's register onto the correct vector.
+  void collect(const MachineOperand &MO, const TargetRegisterInfo *TRI) {
+    if (MO.readsReg()) {
+      if (findReg(MO.getReg(), isVReg, Uses, TRI) == Uses.end())
+      Uses.push_back(MO.getReg());
+    }
+    if (MO.isDef()) {
+      if (MO.isDead()) {
+        if (findReg(MO.getReg(), isVReg, DeadDefs, TRI) == DeadDefs.end())
+          DeadDefs.push_back(MO.getReg());
+      }
+      else {
+        if (findReg(MO.getReg(), isVReg, Defs, TRI) == Defs.end())
+          Defs.push_back(MO.getReg());
+      }
+    }
+  }
+};
+typedef RegisterOperands<false> PhysRegOperands;
+typedef RegisterOperands<true> VirtRegOperands;
+
+/// Collect physical and virtual register operands.
+static void collectOperands(const MachineInstr *MI,
+                            PhysRegOperands &PhysRegOpers,
+                            VirtRegOperands &VirtRegOpers,
+                            const TargetRegisterInfo *TRI,
+                            const RegisterClassInfo *RCI) {
+  for(ConstMIBundleOperands OperI(MI); OperI.isValid(); ++OperI) {
+    const MachineOperand &MO = *OperI;
+    if (!MO.isReg() || !MO.getReg())
+      continue;
+
+    if (TargetRegisterInfo::isVirtualRegister(MO.getReg()))
+      VirtRegOpers.collect(MO, TRI);
+    else if (RCI->isAllocatable(MO.getReg()))
+      PhysRegOpers.collect(MO, TRI);
+  }
+  // Remove redundant physreg dead defs.
+  for (unsigned i = PhysRegOpers.DeadDefs.size(); i > 0; --i) {
+    unsigned Reg = PhysRegOpers.DeadDefs[i-1];
+    if (findRegAlias(Reg, PhysRegOpers.Defs, TRI) != PhysRegOpers.Defs.end())
+      PhysRegOpers.DeadDefs.erase(&PhysRegOpers.DeadDefs[i-1]);
+  }
+}
+
+/// Add PhysReg to the live in set and increase max pressure.
+void RegPressureTracker::discoverPhysLiveIn(unsigned Reg) {
+  assert(!LivePhysRegs.count(Reg) && "avoid bumping max pressure twice");
+  if (findRegAlias(Reg, P.LiveInRegs, TRI) == P.LiveInRegs.end())
+    return;
+
+  // At live in discovery, unconditionally increase the high water mark.
+  P.LiveInRegs.push_back(Reg);
+  P.increase(TRI->getMinimalPhysRegClass(Reg), TRI);
+}
+
+/// Add PhysReg to the live out set and increase max pressure.
+void RegPressureTracker::discoverPhysLiveOut(unsigned Reg) {
+  assert(!LivePhysRegs.count(Reg) && "avoid bumping max pressure twice");
+  if (findRegAlias(Reg, P.LiveOutRegs, TRI) == P.LiveOutRegs.end())
+    return;
+
+  // At live out discovery, unconditionally increase the high water mark.
+  P.LiveOutRegs.push_back(Reg);
+  P.increase(TRI->getMinimalPhysRegClass(Reg), TRI);
+}
+
+/// Add VirtReg to the live in set and increase max pressure.
+void RegPressureTracker::discoverVirtLiveIn(unsigned Reg) {
+  assert(!LiveVirtRegs.count(Reg) && "avoid bumping max pressure twice");
+  if (std::find(P.LiveInRegs.begin(), P.LiveInRegs.end(), Reg) !=
+      P.LiveInRegs.end())
+    return;
+
+  // At live in discovery, unconditionally increase the high water mark.
+  P.LiveInRegs.push_back(Reg);
+  P.increase(MRI->getRegClass(Reg), TRI);
+}
+
+/// Add VirtReg to the live out set and increase max pressure.
+void RegPressureTracker::discoverVirtLiveOut(unsigned Reg) {
+  assert(!LiveVirtRegs.count(Reg) && "avoid bumping max pressure twice");
+  if (std::find(P.LiveOutRegs.begin(), P.LiveOutRegs.end(), Reg) !=
+      P.LiveOutRegs.end())
+    return;
+
+  // At live out discovery, unconditionally increase the high water mark.
+  P.LiveOutRegs.push_back(Reg);
+  P.increase(MRI->getRegClass(Reg), TRI);
+}
+
+/// Recede across the previous instruction.
+bool RegPressureTracker::recede() {
+  // Check for the top of the analyzable region.
+  if (CurrPos == MBB->begin()) {
+    closeRegion();
+    return false;
+  }
+  if (!isBottomClosed())
+    closeBottom();
+
+  // Open the top of the region using block iterators.
+  if (!RequireIntervals && isTopClosed())
+    static_cast<RegionPressure&>(P).openTop(CurrPos);
+
+  // Find the previous instruction.
+  while (--CurrPos != MBB->begin() && CurrPos->isDebugValue());
+
+  if (CurrPos->isDebugValue()) {
+    closeRegion();
+    return false;
+  }
+  SlotIndex SlotIdx;
+  if (RequireIntervals)
+    SlotIdx = LIS->getInstructionIndex(CurrPos).getRegSlot();
+
+  // Open the top of the region using slot indexes.
+  if (RequireIntervals && isTopClosed())
+    static_cast<IntervalPressure&>(P).openTop(SlotIdx);
+
+  PhysRegOperands PhysRegOpers;
+  VirtRegOperands VirtRegOpers;
+  collectOperands(CurrPos, PhysRegOpers, VirtRegOpers, TRI, RCI);
+
+  // Boost pressure for all dead defs together.
+  for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
+      increasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
+      increaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
+      decreasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
+      decreaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+
+  // Kill liveness at live defs.
+  // TODO: consider earlyclobbers?
+  for (unsigned i = 0; i < PhysRegOpers.Defs.size(); ++i) {
+    unsigned Reg = PhysRegOpers.Defs[i];
+    if (LivePhysRegs.erase(Reg))
+      decreasePhysRegPressure(Reg);
+    else
+      discoverPhysLiveOut(Reg);
+  }
+  for (unsigned i = 0; i < VirtRegOpers.Defs.size(); ++i) {
+    unsigned Reg = VirtRegOpers.Defs[i];
+    if (LiveVirtRegs.erase(Reg))
+      decreaseVirtRegPressure(Reg);
+    else
+      discoverVirtLiveOut(Reg);
+  }
+
+  // Generate liveness for uses.
+  for (unsigned i = 0; i < PhysRegOpers.Uses.size(); ++i) {
+    unsigned Reg = PhysRegOpers.Uses[i];
+    if (!hasRegAlias(Reg, LivePhysRegs, TRI)) {
+      increasePhysRegPressure(Reg);
+      LivePhysRegs.insert(Reg);
+    }
+  }
+  for (unsigned i = 0; i < VirtRegOpers.Uses.size(); ++i) {
+    unsigned Reg = VirtRegOpers.Uses[i];
+    if (!LiveVirtRegs.count(Reg)) {
+      // Adjust liveouts if LiveIntervals are available.
+      if (RequireIntervals) {
+        const LiveInterval *LI = &LIS->getInterval(Reg);
+        if (!LI->killedAt(SlotIdx))
+          discoverVirtLiveOut(Reg);
+      }
+      increaseVirtRegPressure(Reg);
+      LiveVirtRegs.insert(Reg);
+    }
+  }
+  return true;
+}
+
+/// Advance across the current instruction.
+bool RegPressureTracker::advance() {
+  // Check for the bottom of the analyzable region.
+  if (CurrPos == MBB->end()) {
+    closeRegion();
+    return false;
+  }
+  if (!isTopClosed())
+    closeTop();
+
+  SlotIndex SlotIdx;
+  if (RequireIntervals)
+    SlotIdx = LIS->getInstructionIndex(CurrPos).getRegSlot();
+
+  // Open the bottom of the region using slot indexes.
+  if (isBottomClosed()) {
+    if (RequireIntervals)
+      static_cast<IntervalPressure&>(P).openBottom(SlotIdx);
+    else
+      static_cast<RegionPressure&>(P).openBottom(CurrPos);
+  }
+
+  PhysRegOperands PhysRegOpers;
+  VirtRegOperands VirtRegOpers;
+  collectOperands(CurrPos, PhysRegOpers, VirtRegOpers, TRI, RCI);
+
+  // Kill liveness at last uses.
+  for (unsigned i = 0; i < PhysRegOpers.Uses.size(); ++i) {
+    unsigned Reg = PhysRegOpers.Uses[i];
+    if (!hasRegAlias(Reg, LivePhysRegs, TRI))
+      discoverPhysLiveIn(Reg);
+    else {
+      // Allocatable physregs are always single-use before regalloc.
+      decreasePhysRegPressure(Reg);
+      LivePhysRegs.erase(Reg);
+    }
+  }
+  for (unsigned i = 0; i < VirtRegOpers.Uses.size(); ++i) {
+    unsigned Reg = VirtRegOpers.Uses[i];
+    if (RequireIntervals) {
+      const LiveInterval *LI = &LIS->getInterval(Reg);
+      if (LI->killedAt(SlotIdx)) {
+        if (LiveVirtRegs.erase(Reg))
+          decreaseVirtRegPressure(Reg);
+        else
+          discoverVirtLiveIn(Reg);
+      }
+    }
+    else if (!LiveVirtRegs.count(Reg)) {
+      discoverVirtLiveIn(Reg);
+      increaseVirtRegPressure(Reg);
+    }
+  }
+
+  // Generate liveness for defs.
+  for (unsigned i = 0; i < PhysRegOpers.Defs.size(); ++i) {
+    unsigned Reg = PhysRegOpers.Defs[i];
+    if (!hasRegAlias(Reg, LivePhysRegs, TRI)) {
+      increasePhysRegPressure(Reg);
+      LivePhysRegs.insert(Reg);
+    }
+  }
+  for (unsigned i = 0; i < VirtRegOpers.Defs.size(); ++i) {
+    unsigned Reg = VirtRegOpers.Defs[i];
+    if (LiveVirtRegs.insert(Reg).second)
+      increaseVirtRegPressure(Reg);
+  }
+
+  // Boost pressure for all dead defs together.
+  for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
+      increasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
+      increaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
+      decreasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
+  for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
+      decreaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+
+  // Find the next instruction.
+  while (++CurrPos != MBB->end() && CurrPos->isDebugValue());
+  return true;
+}