X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FCodeGen%2FMachineRegisterInfo.cpp;h=abf9b4d676960e56bf23071528d53961468f67e6;hp=ef794d5ae3c33e02c4910d4ba940ef09c6f81fc8;hb=dd65ba2dbe6a8cb0fb15818193d011ccd20263a0;hpb=34dcc6fadca0a1117cdbd0e9b35c991a55b6e556

diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp
index ef794d5ae3c..abf9b4d6769 100644
--- a/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/lib/CodeGen/MachineRegisterInfo.cpp
@@ -13,50 +13,76 @@
 
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Support/raw_os_ostream.h"
 #include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+
 using namespace llvm;
 
-MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI) {
+// Pin the vtable to this file.
+void MachineRegisterInfo::Delegate::anchor() {}
+
+MachineRegisterInfo::MachineRegisterInfo(const MachineFunction *MF)
+  : MF(MF), TheDelegate(nullptr), IsSSA(true), TracksLiveness(true),
+    TracksSubRegLiveness(false) {
   VRegInfo.reserve(256);
   RegAllocHints.reserve(256);
-  RegClass2VRegMap.resize(TRI.getNumRegClasses()+1); // RC ID starts at 1.
-  UsedPhysRegs.resize(TRI.getNumRegs());
-  
-  // Create the physreg use/def lists.
-  PhysRegUseDefLists = new MachineOperand*[TRI.getNumRegs()];
-  memset(PhysRegUseDefLists, 0, sizeof(MachineOperand*)*TRI.getNumRegs());
-}
+  UsedPhysRegMask.resize(getTargetRegisterInfo()->getNumRegs());
 
-MachineRegisterInfo::~MachineRegisterInfo() {
-#ifndef NDEBUG
-  for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i)
-    assert(VRegInfo[i].second == 0 && "Vreg use list non-empty still?");
-  for (unsigned i = 0, e = UsedPhysRegs.size(); i != e; ++i)
-    assert(!PhysRegUseDefLists[i] &&
-           "PhysRegUseDefLists has entries after all instructions are deleted");
-#endif
-  delete [] PhysRegUseDefLists;
+  // Create the physreg use/def lists.
+  PhysRegUseDefLists.resize(getTargetRegisterInfo()->getNumRegs(), nullptr);
 }
 
 /// setRegClass - Set the register class of the specified virtual register.
 ///
 void
 MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) {
-  unsigned VR = Reg;
-  Reg -= TargetRegisterInfo::FirstVirtualRegister;
-  assert(Reg < VRegInfo.size() && "Invalid vreg!");
-  const TargetRegisterClass *OldRC = VRegInfo[Reg].first;
+  assert(RC && RC->isAllocatable() && "Invalid RC for virtual register");
   VRegInfo[Reg].first = RC;
+}
+
+const TargetRegisterClass *
+MachineRegisterInfo::constrainRegClass(unsigned Reg,
+                                       const TargetRegisterClass *RC,
+                                       unsigned MinNumRegs) {
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  if (OldRC == RC)
+    return RC;
+  const TargetRegisterClass *NewRC =
+    getTargetRegisterInfo()->getCommonSubClass(OldRC, RC);
+  if (!NewRC || NewRC == OldRC)
+    return NewRC;
+  if (NewRC->getNumRegs() < MinNumRegs)
+    return nullptr;
+  setRegClass(Reg, NewRC);
+  return NewRC;
+}
+
+bool
+MachineRegisterInfo::recomputeRegClass(unsigned Reg) {
+  const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  const TargetRegisterClass *NewRC =
+      getTargetRegisterInfo()->getLargestLegalSuperClass(OldRC, *MF);
 
-  // Remove from old register class's vregs list. This may be slow but
-  // fortunately this operation is rarely needed.
-  std::vector<unsigned> &VRegs = RegClass2VRegMap[OldRC->getID()];
-  std::vector<unsigned>::iterator I=std::find(VRegs.begin(), VRegs.end(), VR);
-  VRegs.erase(I);
+  // Stop early if there is no room to grow.
+  if (NewRC == OldRC)
+    return false;
 
-  // Add to new register class's vregs list.
-  RegClass2VRegMap[RC->getID()].push_back(VR);
+  // Accumulate constraints from all uses.
+  for (MachineOperand &MO : reg_nodbg_operands(Reg)) {
+    // Apply the effect of the given operand to NewRC.
+    MachineInstr *MI = MO.getParent();
+    unsigned OpNo = &MO - &MI->getOperand(0);
+    NewRC = MI->getRegClassConstraintEffect(OpNo, NewRC, TII,
+                                            getTargetRegisterInfo());
+    if (!NewRC || NewRC == OldRC)
+      return false;
+  }
+  setRegClass(Reg, NewRC);
+  return true;
 }
 
 /// createVirtualRegister - Create and return a new virtual register in the
@@ -65,65 +91,235 @@ MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) {
 unsigned
 MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass){
   assert(RegClass && "Cannot create register without RegClass!");
-  // Add a reg, but keep track of whether the vector reallocated or not.
-  void *ArrayBase = VRegInfo.empty() ? 0 : &VRegInfo[0];
-  VRegInfo.push_back(std::make_pair(RegClass, (MachineOperand*)0));
-  RegAllocHints.push_back(std::make_pair(0, 0));
-
-  if (!((&VRegInfo[0] == ArrayBase || VRegInfo.size() == 1)))
-    // The vector reallocated, handle this now.
-    HandleVRegListReallocation();
-  unsigned VR = getLastVirtReg();
-  RegClass2VRegMap[RegClass->getID()].push_back(VR);
-  return VR;
+  assert(RegClass->isAllocatable() &&
+         "Virtual register RegClass must be allocatable.");
+
+  // New virtual register number.
+  unsigned Reg = TargetRegisterInfo::index2VirtReg(getNumVirtRegs());
+  VRegInfo.grow(Reg);
+  VRegInfo[Reg].first = RegClass;
+  RegAllocHints.grow(Reg);
+  if (TheDelegate)
+    TheDelegate->MRI_NoteNewVirtualRegister(Reg);
+  return Reg;
+}
+
+/// clearVirtRegs - Remove all virtual registers (after physreg assignment).
+void MachineRegisterInfo::clearVirtRegs() {
+#ifndef NDEBUG
+  for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i) {
+    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
+    if (!VRegInfo[Reg].second)
+      continue;
+    verifyUseList(Reg);
+    llvm_unreachable("Remaining virtual register operands");
+  }
+#endif
+  VRegInfo.clear();
+  for (auto &I : LiveIns)
+    I.second = 0;
+}
+
+void MachineRegisterInfo::verifyUseList(unsigned Reg) const {
+#ifndef NDEBUG
+  bool Valid = true;
+  for (MachineOperand &M : reg_operands(Reg)) {
+    MachineOperand *MO = &M;
+    MachineInstr *MI = MO->getParent();
+    if (!MI) {
+      errs() << PrintReg(Reg, getTargetRegisterInfo())
+             << " use list MachineOperand " << MO
+             << " has no parent instruction.\n";
+      Valid = false;
+      continue;
+    }
+    MachineOperand *MO0 = &MI->getOperand(0);
+    unsigned NumOps = MI->getNumOperands();
+    if (!(MO >= MO0 && MO < MO0+NumOps)) {
+      errs() << PrintReg(Reg, getTargetRegisterInfo())
+             << " use list MachineOperand " << MO
+             << " doesn't belong to parent MI: " << *MI;
+      Valid = false;
+    }
+    if (!MO->isReg()) {
+      errs() << PrintReg(Reg, getTargetRegisterInfo())
+             << " MachineOperand " << MO << ": " << *MO
+             << " is not a register\n";
+      Valid = false;
+    }
+    if (MO->getReg() != Reg) {
+      errs() << PrintReg(Reg, getTargetRegisterInfo())
+             << " use-list MachineOperand " << MO << ": "
+             << *MO << " is the wrong register\n";
+      Valid = false;
+    }
+  }
+  assert(Valid && "Invalid use list");
+#endif
+}
+
+void MachineRegisterInfo::verifyUseLists() const {
+#ifndef NDEBUG
+  for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i)
+    verifyUseList(TargetRegisterInfo::index2VirtReg(i));
+  for (unsigned i = 1, e = getTargetRegisterInfo()->getNumRegs(); i != e; ++i)
+    verifyUseList(i);
+#endif
+}
+
+/// Add MO to the linked list of operands for its register.
+void MachineRegisterInfo::addRegOperandToUseList(MachineOperand *MO) {
+  assert(!MO->isOnRegUseList() && "Already on list");
+  MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+  MachineOperand *const Head = HeadRef;
+
+  // Head points to the first list element.
+  // Next is NULL on the last list element.
+  // Prev pointers are circular, so Head->Prev == Last.
+
+  // Head is NULL for an empty list.
+  if (!Head) {
+    MO->Contents.Reg.Prev = MO;
+    MO->Contents.Reg.Next = nullptr;
+    HeadRef = MO;
+    return;
+  }
+  assert(MO->getReg() == Head->getReg() && "Different regs on the same list!");
+
+  // Insert MO between Last and Head in the circular Prev chain.
+  MachineOperand *Last = Head->Contents.Reg.Prev;
+  assert(Last && "Inconsistent use list");
+  assert(MO->getReg() == Last->getReg() && "Different regs on the same list!");
+  Head->Contents.Reg.Prev = MO;
+  MO->Contents.Reg.Prev = Last;
+
+  // Def operands always precede uses. This allows def_iterator to stop early.
+  // Insert def operands at the front, and use operands at the back.
+  if (MO->isDef()) {
+    // Insert def at the front.
+    MO->Contents.Reg.Next = Head;
+    HeadRef = MO;
+  } else {
+    // Insert use at the end.
+    MO->Contents.Reg.Next = nullptr;
+    Last->Contents.Reg.Next = MO;
+  }
+}
+
+/// Remove MO from its use-def list.
+void MachineRegisterInfo::removeRegOperandFromUseList(MachineOperand *MO) {
+  assert(MO->isOnRegUseList() && "Operand not on use list");
+  MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+  MachineOperand *const Head = HeadRef;
+  assert(Head && "List already empty");
+
+  // Unlink this from the doubly linked list of operands.
+  MachineOperand *Next = MO->Contents.Reg.Next;
+  MachineOperand *Prev = MO->Contents.Reg.Prev;
+
+  // Prev links are circular, next link is NULL instead of looping back to Head.
+  if (MO == Head)
+    HeadRef = Next;
+  else
+    Prev->Contents.Reg.Next = Next;
+
+  (Next ? Next : Head)->Contents.Reg.Prev = Prev;
+
+  MO->Contents.Reg.Prev = nullptr;
+  MO->Contents.Reg.Next = nullptr;
 }
 
-/// HandleVRegListReallocation - We just added a virtual register to the
-/// VRegInfo info list and it reallocated.  Update the use/def lists info
-/// pointers.
-void MachineRegisterInfo::HandleVRegListReallocation() {
-  // The back pointers for the vreg lists point into the previous vector.
-  // Update them to point to their correct slots.
-  for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i) {
-    MachineOperand *List = VRegInfo[i].second;
-    if (!List) continue;
-    // Update the back-pointer to be accurate once more.
-    List->Contents.Reg.Prev = &VRegInfo[i].second;
+/// Move NumOps operands from Src to Dst, updating use-def lists as needed.
+///
+/// The Dst range is assumed to be uninitialized memory. (Or it may contain
+/// operands that won't be destroyed, which is OK because the MO destructor is
+/// trivial anyway).
+///
+/// The Src and Dst ranges may overlap.
+void MachineRegisterInfo::moveOperands(MachineOperand *Dst,
+                                       MachineOperand *Src,
+                                       unsigned NumOps) {
+  assert(Src != Dst && NumOps && "Noop moveOperands");
+
+  // Copy backwards if Dst is within the Src range.
+  int Stride = 1;
+  if (Dst >= Src && Dst < Src + NumOps) {
+    Stride = -1;
+    Dst += NumOps - 1;
+    Src += NumOps - 1;
   }
+
+  // Copy one operand at a time.
+  do {
+    new (Dst) MachineOperand(*Src);
+
+    // Dst takes Src's place in the use-def chain.
+    if (Src->isReg()) {
+      MachineOperand *&Head = getRegUseDefListHead(Src->getReg());
+      MachineOperand *Prev = Src->Contents.Reg.Prev;
+      MachineOperand *Next = Src->Contents.Reg.Next;
+      assert(Head && "List empty, but operand is chained");
+      assert(Prev && "Operand was not on use-def list");
+
+      // Prev links are circular, next link is NULL instead of looping back to
+      // Head.
+      if (Src == Head)
+        Head = Dst;
+      else
+        Prev->Contents.Reg.Next = Dst;
+
+      // Update Prev pointer. This also works when Src was pointing to itself
+      // in a 1-element list. In that case Head == Dst.
+      (Next ? Next : Head)->Contents.Reg.Prev = Dst;
+    }
+
+    Dst += Stride;
+    Src += Stride;
+  } while (--NumOps);
 }
 
 /// replaceRegWith - Replace all instances of FromReg with ToReg in the
 /// machine function.  This is like llvm-level X->replaceAllUsesWith(Y),
 /// except that it also changes any definitions of the register as well.
+/// If ToReg is a physical register we apply the sub register to obtain the
+/// final/proper physical register.
 void MachineRegisterInfo::replaceRegWith(unsigned FromReg, unsigned ToReg) {
   assert(FromReg != ToReg && "Cannot replace a reg with itself");
 
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  
   // TODO: This could be more efficient by bulk changing the operands.
   for (reg_iterator I = reg_begin(FromReg), E = reg_end(); I != E; ) {
-    MachineOperand &O = I.getOperand();
+    MachineOperand &O = *I;
     ++I;
-    O.setReg(ToReg);
+    if (TargetRegisterInfo::isPhysicalRegister(ToReg)) {
+      O.substPhysReg(ToReg, *TRI);
+    } else {
+      O.setReg(ToReg);
+    }
   }
 }
 
-
 /// getVRegDef - Return the machine instr that defines the specified virtual
 /// register or null if none is found.  This assumes that the code is in SSA
 /// form, so there should only be one definition.
 MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const {
-  assert(Reg-TargetRegisterInfo::FirstVirtualRegister < VRegInfo.size() &&
-         "Invalid vreg!");
   // Since we are in SSA form, we can use the first definition.
-  if (!def_empty(Reg))
-    return &*def_begin(Reg);
-  return 0;
+  def_instr_iterator I = def_instr_begin(Reg);
+  assert((I.atEnd() || std::next(I) == def_instr_end()) &&
+         "getVRegDef assumes a single definition or no definition");
+  return !I.atEnd() ? &*I : nullptr;
 }
 
-bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const {
-  use_iterator UI = use_begin(RegNo);
-  if (UI == use_end())
-    return false;
-  return ++UI == use_end();
+/// getUniqueVRegDef - Return the unique machine instr that defines the
+/// specified virtual register or null if none is found.  If there are
+/// multiple definitions or no definition, return null.
+MachineInstr *MachineRegisterInfo::getUniqueVRegDef(unsigned Reg) const {
+  if (def_empty(Reg)) return nullptr;
+  def_instr_iterator I = def_instr_begin(Reg);
+  if (std::next(I) != def_instr_end())
+    return nullptr;
+  return &*I;
 }
 
 bool MachineRegisterInfo::hasOneNonDBGUse(unsigned RegNo) const {
@@ -133,6 +329,15 @@ bool MachineRegisterInfo::hasOneNonDBGUse(unsigned RegNo) const {
   return ++UI == use_nodbg_end();
 }
 
+/// clearKillFlags - Iterate over all the uses of the given register and
+/// clear the kill flag from the MachineOperand. This function is used by
+/// optimization passes which extend register lifetimes and need only
+/// preserve conservative kill flag information.
+void MachineRegisterInfo::clearKillFlags(unsigned Reg) const {
+  for (MachineOperand &MO : use_operands(Reg))
+    MO.setIsKill(false);
+}
+
 bool MachineRegisterInfo::isLiveIn(unsigned Reg) const {
   for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
     if (I->first == Reg || I->second == Reg)
@@ -140,13 +345,6 @@ bool MachineRegisterInfo::isLiveIn(unsigned Reg) const {
   return false;
 }
 
-bool MachineRegisterInfo::isLiveOut(unsigned Reg) const {
-  for (liveout_iterator I = liveout_begin(), E = liveout_end(); I != E; ++I)
-    if (*I == Reg)
-      return true;
-  return false;
-}
-
 /// getLiveInPhysReg - If VReg is a live-in virtual register, return the
 /// corresponding live-in physical register.
 unsigned MachineRegisterInfo::getLiveInPhysReg(unsigned VReg) const {
@@ -156,78 +354,13 @@ unsigned MachineRegisterInfo::getLiveInPhysReg(unsigned VReg) const {
   return 0;
 }
 
-static cl::opt<bool>
-SchedLiveInCopies("schedule-livein-copies", cl::Hidden,
-                  cl::desc("Schedule copies of livein registers"),
-                  cl::init(false));
-
-/// EmitLiveInCopy - Emit a copy for a live in physical register. If the
-/// physical register has only a single copy use, then coalesced the copy
-/// if possible.
-static void EmitLiveInCopy(MachineBasicBlock *MBB,
-                           MachineBasicBlock::iterator &InsertPos,
-                           unsigned VirtReg, unsigned PhysReg,
-                           const TargetRegisterClass *RC,
-                           DenseMap<MachineInstr*, unsigned> &CopyRegMap,
-                           const MachineRegisterInfo &MRI,
-                           const TargetRegisterInfo &TRI,
-                           const TargetInstrInfo &TII) {
-  unsigned NumUses = 0;
-  MachineInstr *UseMI = NULL;
-  for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg),
-         UE = MRI.use_end(); UI != UE; ++UI) {
-    UseMI = &*UI;
-    if (++NumUses > 1)
-      break;
-  }
-
-  // If the number of uses is not one, or the use is not a move instruction,
-  // don't coalesce. Also, only coalesce away a virtual register to virtual
-  // register copy.
-  bool Coalesced = false;
-  unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
-  if (NumUses == 1 &&
-      TII.isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubReg, DstSubReg) &&
-      TargetRegisterInfo::isVirtualRegister(DstReg)) {
-    VirtReg = DstReg;
-    Coalesced = true;
-  }
-
-  // Now find an ideal location to insert the copy.
-  MachineBasicBlock::iterator Pos = InsertPos;
-  while (Pos != MBB->begin()) {
-    MachineInstr *PrevMI = prior(Pos);
-    DenseMap<MachineInstr*, unsigned>::iterator RI = CopyRegMap.find(PrevMI);
-    // copyRegToReg might emit multiple instructions to do a copy.
-    unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second;
-    if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg))
-      // This is what the BB looks like right now:
-      // r1024 = mov r0
-      // ...
-      // r1    = mov r1024
-      //
-      // We want to insert "r1025 = mov r1". Inserting this copy below the
-      // move to r1024 makes it impossible for that move to be coalesced.
-      //
-      // r1025 = mov r1
-      // r1024 = mov r0
-      // ...
-      // r1    = mov 1024
-      // r2    = mov 1025
-      break; // Woot! Found a good location.
-    --Pos;
-  }
-
-  bool Emitted = TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC,
-                                  DebugLoc());
-  assert(Emitted && "Unable to issue a live-in copy instruction!\n");
-  (void) Emitted;
-
-  CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg));
-  if (Coalesced) {
-    if (&*InsertPos == UseMI) ++InsertPos;
-    MBB->erase(UseMI);
-  }
+/// getLiveInVirtReg - If PReg is a live-in physical register, return the
+/// corresponding live-in physical register.
+unsigned MachineRegisterInfo::getLiveInVirtReg(unsigned PReg) const {
+  for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
+    if (I->first == PReg)
+      return I->second;
+  return 0;
 }
 
 /// EmitLiveInCopies - Emit copies to initialize livein virtual registers
@@ -236,40 +369,131 @@ void
 MachineRegisterInfo::EmitLiveInCopies(MachineBasicBlock *EntryMBB,
                                       const TargetRegisterInfo &TRI,
                                       const TargetInstrInfo &TII) {
-  if (SchedLiveInCopies) {
-    // Emit the copies at a heuristically-determined location in the block.
-    DenseMap<MachineInstr*, unsigned> CopyRegMap;
-    MachineBasicBlock::iterator InsertPos = EntryMBB->begin();
-    for (MachineRegisterInfo::livein_iterator LI = livein_begin(),
-           E = livein_end(); LI != E; ++LI)
-      if (LI->second) {
-        const TargetRegisterClass *RC = getRegClass(LI->second);
-        EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first,
-                       RC, CopyRegMap, *this, TRI, TII);
-      }
-  } else {
-    // Emit the copies into the top of the block.
-    for (MachineRegisterInfo::livein_iterator LI = livein_begin(),
-           E = livein_end(); LI != E; ++LI)
-      if (LI->second) {
-        const TargetRegisterClass *RC = getRegClass(LI->second);
-        bool Emitted = TII.copyRegToReg(*EntryMBB, EntryMBB->begin(),
-                                        LI->second, LI->first, RC, RC,
-                                        DebugLoc());
-        assert(Emitted && "Unable to issue a live-in copy instruction!\n");
-        (void) Emitted;
+  // Emit the copies into the top of the block.
+  for (unsigned i = 0, e = LiveIns.size(); i != e; ++i)
+    if (LiveIns[i].second) {
+      if (use_empty(LiveIns[i].second)) {
+        // The livein has no uses. Drop it.
+        //
+        // It would be preferable to have isel avoid creating live-in
+        // records for unused arguments in the first place, but it's
+        // complicated by the debug info code for arguments.
+        LiveIns.erase(LiveIns.begin() + i);
+        --i; --e;
+      } else {
+        // Emit a copy.
+        BuildMI(*EntryMBB, EntryMBB->begin(), DebugLoc(),
+                TII.get(TargetOpcode::COPY), LiveIns[i].second)
+          .addReg(LiveIns[i].first);
+
+        // Add the register to the entry block live-in set.
+        EntryMBB->addLiveIn(LiveIns[i].first);
       }
-  }
+    } else {
+      // Add the register to the entry block live-in set.
+      EntryMBB->addLiveIn(LiveIns[i].first);
+    }
+}
 
-  // Add function live-ins to entry block live-in set.
-  for (MachineRegisterInfo::livein_iterator I = livein_begin(),
-       E = livein_end(); I != E; ++I)
-    EntryMBB->addLiveIn(I->first);
+LaneBitmask MachineRegisterInfo::getMaxLaneMaskForVReg(unsigned Reg) const {
+  // Lane masks are only defined for vregs.
+  assert(TargetRegisterInfo::isVirtualRegister(Reg));
+  const TargetRegisterClass &TRC = *getRegClass(Reg);
+  return TRC.getLaneMask();
 }
 
 #ifndef NDEBUG
 void MachineRegisterInfo::dumpUses(unsigned Reg) const {
-  for (use_iterator I = use_begin(Reg), E = use_end(); I != E; ++I)
-    I.getOperand().getParent()->dump();
+  for (MachineInstr &I : use_instructions(Reg))
+    I.dump();
 }
 #endif
+
+void MachineRegisterInfo::freezeReservedRegs(const MachineFunction &MF) {
+  ReservedRegs = getTargetRegisterInfo()->getReservedRegs(MF);
+  assert(ReservedRegs.size() == getTargetRegisterInfo()->getNumRegs() &&
+         "Invalid ReservedRegs vector from target");
+}
+
+bool MachineRegisterInfo::isConstantPhysReg(unsigned PhysReg,
+                                            const MachineFunction &MF) const {
+  assert(TargetRegisterInfo::isPhysicalRegister(PhysReg));
+
+  // Check if any overlapping register is modified, or allocatable so it may be
+  // used later.
+  for (MCRegAliasIterator AI(PhysReg, getTargetRegisterInfo(), true);
+       AI.isValid(); ++AI)
+    if (!def_empty(*AI) || isAllocatable(*AI))
+      return false;
+  return true;
+}
+
+/// markUsesInDebugValueAsUndef - Mark every DBG_VALUE referencing the
+/// specified register as undefined which causes the DBG_VALUE to be
+/// deleted during LiveDebugVariables analysis.
+void MachineRegisterInfo::markUsesInDebugValueAsUndef(unsigned Reg) const {
+  // Mark any DBG_VALUE that uses Reg as undef (but don't delete it.)
+  MachineRegisterInfo::use_instr_iterator nextI;
+  for (use_instr_iterator I = use_instr_begin(Reg), E = use_instr_end();
+       I != E; I = nextI) {
+    nextI = std::next(I);  // I is invalidated by the setReg
+    MachineInstr *UseMI = &*I;
+    if (UseMI->isDebugValue())
+      UseMI->getOperand(0).setReg(0U);
+  }
+}
+
+static const Function *getCalledFunction(const MachineInstr &MI) {
+  for (const MachineOperand &MO : MI.operands()) {
+    if (!MO.isGlobal())
+      continue;
+    const Function *Func = dyn_cast<Function>(MO.getGlobal());
+    if (Func != nullptr)
+      return Func;
+  }
+  return nullptr;
+}
+
+static bool isNoReturnDef(const MachineOperand &MO) {
+  // Anything which is not a noreturn function is a real def.
+  const MachineInstr &MI = *MO.getParent();
+  if (!MI.isCall())
+    return false;
+  const MachineBasicBlock &MBB = *MI.getParent();
+  if (!MBB.succ_empty())
+    return false;
+  const MachineFunction &MF = *MBB.getParent();
+  // We need to keep correct unwind information even if the function will
+  // not return, since the runtime may need it.
+  if (MF.getFunction()->hasFnAttribute(Attribute::UWTable))
+    return false;
+  const Function *Called = getCalledFunction(MI);
+  return !(Called == nullptr || !Called->hasFnAttribute(Attribute::NoReturn) ||
+           !Called->hasFnAttribute(Attribute::NoUnwind));
+}
+
+bool MachineRegisterInfo::isPhysRegModified(unsigned PhysReg) const {
+  if (UsedPhysRegMask.test(PhysReg))
+    return true;
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI) {
+    for (const MachineOperand &MO : make_range(def_begin(*AI), def_end())) {
+      if (isNoReturnDef(MO))
+        continue;
+      return true;
+    }
+  }
+  return false;
+}
+
+bool MachineRegisterInfo::isPhysRegUsed(unsigned PhysReg) const {
+  if (UsedPhysRegMask.test(PhysReg))
+    return true;
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  for (MCRegAliasIterator AliasReg(PhysReg, TRI, true); AliasReg.isValid();
+       ++AliasReg) {
+    if (!reg_nodbg_empty(*AliasReg))
+      return true;
+  }
+  return false;
+}