diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -800,7 +800,7 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
           // This is bad, if an interrupt is taken after the mov, sp is in an
           // inconsistent state.
           // Use the first callee-saved register as a scratch register.
-          assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) &&
+          assert(!MFI->getPristineRegs(MF).test(ARM::R4) &&
                  "No scratch register to restore SP from FP!");
           emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::R4, FramePtr, -NumBytes,
                                  ARMCC::AL, 0, TII);
@@ -1470,7 +1470,8 @@ static unsigned estimateRSStackSizeLimit(MachineFunction &MF,
 // callee-saved vector registers after realigning the stack. The vst1 and vld1
 // instructions take alignment hints that can improve performance.
 //
-static void checkNumAlignedDPRCS2Regs(MachineFunction &MF) {
+static void
+checkNumAlignedDPRCS2Regs(MachineFunction &MF, BitVector &SavedRegs) {
   MF.getInfo<ARMFunctionInfo>()->setNumAlignedDPRCS2Regs(0);
   if (!SpillAlignedNEONRegs)
     return;
@@ -1497,10 +1498,9 @@ static void checkNumAlignedDPRCS2Regs(MachineFunction &MF) {
   // callee-saved registers in order, but it can happen that there are holes in
   // the range.  Registers above the hole will be spilled to the standard DPRCS
   // area.
-  MachineRegisterInfo &MRI = MF.getRegInfo();
   unsigned NumSpills = 0;
   for (; NumSpills < 8; ++NumSpills)
-    if (!MRI.isPhysRegUsed(ARM::D8 + NumSpills))
+    if (!SavedRegs.test(ARM::D8 + NumSpills))
       break;
 
   // Don't do this for just one d-register. It's not worth it.
@@ -1511,12 +1511,13 @@ static void checkNumAlignedDPRCS2Regs(MachineFunction &MF) {
   MF.getInfo<ARMFunctionInfo>()->setNumAlignedDPRCS2Regs(NumSpills);
 
   // A scratch register is required for the vst1 / vld1 instructions.
-  MF.getRegInfo().setPhysRegUsed(ARM::R4);
+  SavedRegs.set(ARM::R4);
 }
 
-void
-ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                                       RegScavenger *RS) const {
+void ARMFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                            BitVector &SavedRegs,
+                                            RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
   // This tells PEI to spill the FP as if it is any other callee-save register
   // to take advantage the eliminateFrameIndex machinery. This also ensures it
   // is spilled in the order specified by getCalleeSavedRegs() to make it easier
@@ -1543,12 +1544,12 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   // FIXME: It will be better just to find spare register here.
   if (AFI->isThumb2Function() &&
       (MFI->hasVarSizedObjects() || RegInfo->needsStackRealignment(MF)))
-    MRI.setPhysRegUsed(ARM::R4);
+    SavedRegs.set(ARM::R4);
 
   if (AFI->isThumb1OnlyFunction()) {
     // Spill LR if Thumb1 function uses variable length argument lists.
     if (AFI->getArgRegsSaveSize() > 0)
-      MRI.setPhysRegUsed(ARM::LR);
+      SavedRegs.set(ARM::LR);
 
     // Spill R4 if Thumb1 epilogue has to restore SP from FP. We don't know
     // for sure what the stack size will be, but for this, an estimate is good
@@ -1558,23 +1559,23 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     // FIXME: It will be better just to find spare register here.
     unsigned StackSize = MFI->estimateStackSize(MF);
     if (MFI->hasVarSizedObjects() || StackSize > 508)
-      MRI.setPhysRegUsed(ARM::R4);
+      SavedRegs.set(ARM::R4);
   }
 
   // See if we can spill vector registers to aligned stack.
-  checkNumAlignedDPRCS2Regs(MF);
+  checkNumAlignedDPRCS2Regs(MF, SavedRegs);
 
   // Spill the BasePtr if it's used.
   if (RegInfo->hasBasePointer(MF))
-    MRI.setPhysRegUsed(RegInfo->getBaseRegister());
+    SavedRegs.set(RegInfo->getBaseRegister());
 
   // Don't spill FP if the frame can be eliminated. This is determined
-  // by scanning the callee-save registers to see if any is used.
+  // by scanning the callee-save registers to see if any is modified.
   const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&MF);
   for (unsigned i = 0; CSRegs[i]; ++i) {
     unsigned Reg = CSRegs[i];
     bool Spilled = false;
-    if (MRI.isPhysRegUsed(Reg)) {
+    if (SavedRegs.test(Reg)) {
       Spilled = true;
       CanEliminateFrame = false;
     }
@@ -1668,7 +1669,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
     // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
     if (!LRSpilled && CS1Spilled) {
-      MRI.setPhysRegUsed(ARM::LR);
+      SavedRegs.set(ARM::LR);
       NumGPRSpills++;
       SmallVectorImpl<unsigned>::iterator LRPos;
       LRPos = std::find(UnspilledCS1GPRs.begin(), UnspilledCS1GPRs.end(),
@@ -1681,7 +1682,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     }
 
     if (hasFP(MF)) {
-      MRI.setPhysRegUsed(FramePtr);
+      SavedRegs.set(FramePtr);
       auto FPPos = std::find(UnspilledCS1GPRs.begin(), UnspilledCS1GPRs.end(),
                              FramePtr);
       if (FPPos != UnspilledCS1GPRs.end())
@@ -1700,15 +1701,15 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
           // Don't spill high register if the function is thumb
           if (!AFI->isThumbFunction() ||
               isARMLowRegister(Reg) || Reg == ARM::LR) {
-            MRI.setPhysRegUsed(Reg);
+            SavedRegs.set(Reg);
             if (!MRI.isReserved(Reg))
               ExtraCSSpill = true;
             break;
           }
         }
       } else if (!UnspilledCS2GPRs.empty() && !AFI->isThumb1OnlyFunction()) {
         unsigned Reg = UnspilledCS2GPRs.front();
-        MRI.setPhysRegUsed(Reg);
+        SavedRegs.set(Reg);
         if (!MRI.isReserved(Reg))
           ExtraCSSpill = true;
       }
@@ -1747,7 +1748,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
       }
       if (Extras.size() && NumExtras == 0) {
         for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
-          MRI.setPhysRegUsed(Extras[i]);
+          SavedRegs.set(Extras[i]);
         }
       } else if (!AFI->isThumb1OnlyFunction()) {
         // note: Thumb1 functions spill to R12, not the stack.  Reserve a slot
@@ -1761,7 +1762,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   }
 
   if (ForceLRSpill) {
-    MRI.setPhysRegUsed(ARM::LR);
+    SavedRegs.set(ARM::LR);
     AFI->setLRIsSpilledForFarJump(true);
   }
 }

diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.h b/llvm/lib/Target/ARM/ARMFrameLowering.h
@@ -54,8 +54,8 @@ class ARMFrameLowering : public TargetFrameLowering {
                                  unsigned &FrameReg, int SPAdj) const;
   int getFrameIndexOffset(const MachineFunction &MF, int FI) const override;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                            RegScavenger *RS) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS) const override;
 
   void adjustForSegmentedStacks(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const override;

diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -365,7 +365,7 @@ void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF,
       // frame pointer stack slot, the target is ELF and the function has FP, or
       // the target uses var sized objects.
       if (NumBytes) {
-        assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) &&
+        assert(!MFI->getPristineRegs(MF).test(ARM::R4) &&
                "No scratch register to restore SP from FP!");
         emitThumbRegPlusImmediate(MBB, MBBI, dl, ARM::R4, FramePtr, -NumBytes,
                                   TII, *RegInfo);

diff --git a/llvm/lib/Target/BPF/BPFFrameLowering.cpp b/llvm/lib/Target/BPF/BPFFrameLowering.cpp
@@ -29,12 +29,12 @@ void BPFFrameLowering::emitPrologue(MachineFunction &MF,
 void BPFFrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {}
 
-void BPFFrameLowering::processFunctionBeforeCalleeSavedScan(
-    MachineFunction &MF, RegScavenger *RS) const {
-  MachineRegisterInfo &MRI = MF.getRegInfo();
-
-  MRI.setPhysRegUnused(BPF::R6);
-  MRI.setPhysRegUnused(BPF::R7);
-  MRI.setPhysRegUnused(BPF::R8);
-  MRI.setPhysRegUnused(BPF::R9);
+void BPFFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                            BitVector &SavedRegs,
+                                            RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+  SavedRegs.reset(BPF::R6);
+  SavedRegs.reset(BPF::R7);
+  SavedRegs.reset(BPF::R8);
+  SavedRegs.reset(BPF::R9);
 }
diff --git a/llvm/lib/Target/BPF/BPFFrameLowering.h b/llvm/lib/Target/BPF/BPFFrameLowering.h
@@ -28,8 +28,8 @@ class BPFFrameLowering : public TargetFrameLowering {
   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
 
   bool hasFP(const MachineFunction &MF) const override;
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                            RegScavenger *RS) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS) const override;
 
   void
   eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,

diff --git a/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp b/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
@@ -959,8 +959,11 @@ bool HexagonFrameLowering::replacePredRegPseudoSpillCode(MachineFunction &MF)
 }
 
 
-void HexagonFrameLowering::processFunctionBeforeCalleeSavedScan(
-      MachineFunction &MF, RegScavenger* RS) const {
+void HexagonFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                                BitVector &SavedRegs,
+                                                RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
   auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
   auto &HRI = *HST.getRegisterInfo();
 
@@ -969,11 +972,9 @@ void HexagonFrameLowering::processFunctionBeforeCalleeSavedScan(
   // If we have a function containing __builtin_eh_return we want to spill and
   // restore all callee saved registers. Pretend that they are used.
   if (HasEHReturn) {
-    MachineRegisterInfo &MRI = MF.getRegInfo();
     for (const MCPhysReg *CSRegs = HRI.getCalleeSavedRegs(&MF); *CSRegs;
          ++CSRegs)
-      if (!MRI.isPhysRegUsed(*CSRegs))
-        MRI.setPhysRegUsed(*CSRegs);
+      SavedRegs.set(*CSRegs);
   }
 
   const TargetRegisterClass &RC = Hexagon::IntRegsRegClass;

diff --git a/llvm/lib/Target/Hexagon/HexagonFrameLowering.h b/llvm/lib/Target/Hexagon/HexagonFrameLowering.h
@@ -45,7 +45,7 @@ class HexagonFrameLowering : public TargetFrameLowering {
       MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const override;
   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
         RegScavenger *RS = nullptr) const override;
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
         RegScavenger *RS) const override;
 
   bool targetHandlesStackFrameRounding() const override {

diff --git a/llvm/lib/Target/Mips/Mips16FrameLowering.cpp b/llvm/lib/Target/Mips/Mips16FrameLowering.cpp
@@ -152,18 +152,19 @@ Mips16FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
   return isInt<15>(MFI->getMaxCallFrameSize()) && !MFI->hasVarSizedObjects();
 }
 
-void Mips16FrameLowering::
-processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS) const {
+void Mips16FrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                               BitVector &SavedRegs,
+                                               RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
   const Mips16InstrInfo &TII =
       *static_cast<const Mips16InstrInfo *>(STI.getInstrInfo());
   const MipsRegisterInfo &RI = TII.getRegisterInfo();
   const BitVector Reserved = RI.getReservedRegs(MF);
   bool SaveS2 = Reserved[Mips::S2];
   if (SaveS2)
-    MF.getRegInfo().setPhysRegUsed(Mips::S2);
+    SavedRegs.set(Mips::S2);
   if (hasFP(MF))
-    MF.getRegInfo().setPhysRegUsed(Mips::S0);
+    SavedRegs.set(Mips::S0);
 }
 
 const MipsFrameLowering *

diff --git a/llvm/lib/Target/Mips/Mips16FrameLowering.h b/llvm/lib/Target/Mips/Mips16FrameLowering.h
@@ -38,8 +38,8 @@ class Mips16FrameLowering : public MipsFrameLowering {
 
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                            RegScavenger *RS) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS) const override;
 };
 
 } // End llvm namespace

diff --git a/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp b/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp
@@ -621,21 +621,28 @@ MipsSEFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
     !MFI->hasVarSizedObjects();
 }
 
-void MipsSEFrameLowering::
-processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS) const {
-  MachineRegisterInfo &MRI = MF.getRegInfo();
+/// Mark \p Reg and all registers aliasing it in the bitset.
+void setAliasRegs(MachineFunction &MF, BitVector &SavedRegs, unsigned Reg) {
+  const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    SavedRegs.set(*AI);
+}
+
+void MipsSEFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                               BitVector &SavedRegs,
+                                               RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
   MipsABIInfo ABI = STI.getABI();
   unsigned FP = ABI.GetFramePtr();
   unsigned BP = ABI.IsN64() ? Mips::S7_64 : Mips::S7;
 
   // Mark $fp as used if function has dedicated frame pointer.
   if (hasFP(MF))
-    MRI.setPhysRegUsed(FP);
+    setAliasRegs(MF, SavedRegs, FP);
   // Mark $s7 as used if function has dedicated base pointer.
   if (hasBP(MF))
-    MRI.setPhysRegUsed(BP);
+    setAliasRegs(MF, SavedRegs, BP);
 
   // Create spill slots for eh data registers if function calls eh_return.
   if (MipsFI->callsEhReturn())

diff --git a/llvm/lib/Target/Mips/MipsSEFrameLowering.h b/llvm/lib/Target/Mips/MipsSEFrameLowering.h
@@ -34,8 +34,8 @@ class MipsSEFrameLowering : public MipsFrameLowering {
 
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                            RegScavenger *RS) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS) const override;
   unsigned ehDataReg(unsigned I) const;
 };
 

diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1158,18 +1158,19 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
   }
 }
 
-void
-PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                                   RegScavenger *) const {
+void PPCFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                            BitVector &SavedRegs,
+                                            RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
   const PPCRegisterInfo *RegInfo =
       static_cast<const PPCRegisterInfo *>(Subtarget.getRegisterInfo());
 
   //  Save and clear the LR state.
   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
   unsigned LR = RegInfo->getRARegister();
   FI->setMustSaveLR(MustSaveLR(MF, LR));
-  MachineRegisterInfo &MRI = MF.getRegInfo();
-  MRI.setPhysRegUnused(LR);
+  SavedRegs.reset(LR);
 
   //  Save R31 if necessary
   int FPSI = FI->getFramePointerSaveIndex();
@@ -1214,9 +1215,9 @@ PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   // For 32-bit SVR4, allocate the nonvolatile CR spill slot iff the
   // function uses CR 2, 3, or 4.
   if (!isPPC64 && !isDarwinABI &&
-      (MRI.isPhysRegUsed(PPC::CR2) ||
-       MRI.isPhysRegUsed(PPC::CR3) ||
-       MRI.isPhysRegUsed(PPC::CR4))) {
+      (SavedRegs.test(PPC::CR2) ||
+       SavedRegs.test(PPC::CR3) ||
+       SavedRegs.test(PPC::CR4))) {
     int FrameIdx = MFI->CreateFixedObject((uint64_t)4, (int64_t)-4, true);
     FI->setCRSpillFrameIndex(FrameIdx);
   }

diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.h b/llvm/lib/Target/PowerPC/PPCFrameLowering.h
@@ -45,8 +45,8 @@ class PPCFrameLowering: public TargetFrameLowering {
   bool needsFP(const MachineFunction &MF) const;
   void replaceFPWithRealFP(MachineFunction &MF) const;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS = nullptr) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS = nullptr) const override;
   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                      RegScavenger *RS = nullptr) const override;
   void addScavengingSpillSlot(MachineFunction &MF, RegScavenger *RS) const;

diff --git a/llvm/lib/Target/Sparc/SparcFrameLowering.cpp b/llvm/lib/Target/Sparc/SparcFrameLowering.cpp
@@ -247,9 +247,10 @@ void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
 #endif
 }
 
-void SparcFrameLowering::processFunctionBeforeCalleeSavedScan
-                  (MachineFunction &MF, RegScavenger *RS) const {
-
+void SparcFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                              BitVector &SavedRegs,
+                                              RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
   if (!DisableLeafProc && isLeafProc(MF)) {
     SparcMachineFunctionInfo *MFI = MF.getInfo<SparcMachineFunctionInfo>();
     MFI->setLeafProc(true);

diff --git a/llvm/lib/Target/Sparc/SparcFrameLowering.h b/llvm/lib/Target/Sparc/SparcFrameLowering.h
@@ -36,8 +36,8 @@ class SparcFrameLowering : public TargetFrameLowering {
 
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
   bool hasFP(const MachineFunction &MF) const override;
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS = nullptr) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS = nullptr) const override;
 
 private:
   // Remap input registers to output registers for leaf procedure.

diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -61,11 +61,12 @@ SystemZFrameLowering::getCalleeSavedSpillSlots(unsigned &NumEntries) const {
   return SpillOffsetTable;
 }
 
-void SystemZFrameLowering::
-processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS) const {
+void SystemZFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                                BitVector &SavedRegs,
+                                                RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
   MachineFrameInfo *MFFrame = MF.getFrameInfo();
-  MachineRegisterInfo &MRI = MF.getRegInfo();
   const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
   bool HasFP = hasFP(MF);
   SystemZMachineFunctionInfo *MFI = MF.getInfo<SystemZMachineFunctionInfo>();
@@ -77,17 +78,17 @@ processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   // argument register R6D.
   if (IsVarArg)
     for (unsigned I = MFI->getVarArgsFirstGPR(); I < SystemZ::NumArgGPRs; ++I)
-      MRI.setPhysRegUsed(SystemZ::ArgGPRs[I]);
+      SavedRegs.set(SystemZ::ArgGPRs[I]);
 
   // If the function requires a frame pointer, record that the hard
   // frame pointer will be clobbered.
   if (HasFP)
-    MRI.setPhysRegUsed(SystemZ::R11D);
+    SavedRegs.set(SystemZ::R11D);
 
   // If the function calls other functions, record that the return
   // address register will be clobbered.
   if (MFFrame->hasCalls())
-    MRI.setPhysRegUsed(SystemZ::R14D);
+    SavedRegs.set(SystemZ::R14D);
 
   // If we are saving GPRs other than the stack pointer, we might as well
   // save and restore the stack pointer at the same time, via STMG and LMG.
@@ -96,8 +97,8 @@ processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
   for (unsigned I = 0; CSRegs[I]; ++I) {
     unsigned Reg = CSRegs[I];
-    if (SystemZ::GR64BitRegClass.contains(Reg) && MRI.isPhysRegUsed(Reg)) {
-      MRI.setPhysRegUsed(SystemZ::R15D);
+    if (SystemZ::GR64BitRegClass.contains(Reg) && SavedRegs.test(Reg)) {
+      SavedRegs.set(SystemZ::R15D);
       break;
     }
   }

diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.h b/llvm/lib/Target/SystemZ/SystemZFrameLowering.h
@@ -27,8 +27,8 @@ class SystemZFrameLowering : public TargetFrameLowering {
   bool isFPCloseToIncomingSP() const override { return false; }
   const SpillSlot *getCalleeSavedSpillSlots(unsigned &NumEntries) const
     override;
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                            RegScavenger *RS) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS) const override;
   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator MBBI,
                                  const std::vector<CalleeSavedInfo> &CSI,

diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -1425,9 +1425,11 @@ bool X86FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
   return true;
 }
 
-void
-X86FrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                                       RegScavenger *RS) const {
+void X86FrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                            BitVector &SavedRegs,
+                                            RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
   MachineFrameInfo *MFI = MF.getFrameInfo();
 
   X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
@@ -1449,7 +1451,7 @@ X86FrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
 
   // Spill the BasePtr if it's used.
   if (TRI->hasBasePointer(MF))
-    MF.getRegInfo().setPhysRegUsed(TRI->getBaseRegister());
+    SavedRegs.set(TRI->getBaseRegister());
 }
 
 static bool

diff --git a/llvm/lib/Target/X86/X86FrameLowering.h b/llvm/lib/Target/X86/X86FrameLowering.h
@@ -68,8 +68,8 @@ class X86FrameLowering : public TargetFrameLowering {
   void adjustForHiPEPrologue(MachineFunction &MF,
                              MachineBasicBlock &PrologueMBB) const override;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS = nullptr) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS = nullptr) const override;
 
   bool
   assignCalleeSavedSpillSlots(MachineFunction &MF,

diff --git a/llvm/lib/Target/XCore/XCoreFrameLowering.cpp b/llvm/lib/Target/XCore/XCoreFrameLowering.cpp
@@ -525,12 +525,15 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
   MBB.erase(I);
 }
 
-void XCoreFrameLowering::
-processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS) const {
+void XCoreFrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                              BitVector &SavedRegs,
+                                              RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+
   XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
 
-  bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
+  const MachineRegisterInfo &MRI = MF.getRegInfo();
+  bool LRUsed = MRI.isPhysRegModified(XCore::LR);
 
   if (!LRUsed && !MF.getFunction()->isVarArg() &&
       MF.getFrameInfo()->estimateStackSize(MF))
@@ -550,7 +553,7 @@ processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   if (LRUsed) {
     // We will handle the LR in the prologue/epilogue
     // and allocate space on the stack ourselves.
-    MF.getRegInfo().setPhysRegUnused(XCore::LR);
+    SavedRegs.reset(XCore::LR);
     XFI->createLRSpillSlot(MF);
   }
 

diff --git a/llvm/lib/Target/XCore/XCoreFrameLowering.h b/llvm/lib/Target/XCore/XCoreFrameLowering.h
@@ -47,8 +47,8 @@ namespace llvm {
 
     bool hasFP(const MachineFunction &MF) const override;
 
-    void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS = nullptr) const override;
+    void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                              RegScavenger *RS = nullptr) const override;
 
     void processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                      RegScavenger *RS = nullptr) const override;

diff --git a/llvm/test/CodeGen/ARM/arm-returnaddr.ll b/llvm/test/CodeGen/ARM/arm-returnaddr.ll
@@ -8,7 +8,6 @@
 define i8* @rt0(i32 %x) nounwind readnone {
 entry:
 ; CHECK-LABEL: rt0:
-; CHECK: {r7, lr}
 ; CHECK: mov r0, lr
   %0 = tail call i8* @llvm.returnaddress(i32 0)
   ret i8* %0
@@ -17,10 +16,9 @@ entry:
 define i8* @rt2() nounwind readnone {
 entry:
 ; CHECK-LABEL: rt2:
-; CHECK: {r7, lr}
 ; CHECK: ldr r[[R0:[0-9]+]], [r7]
-; CHECK: ldr r0, [r0]
-; CHECK: ldr r0, [r0, #4]
+; CHECK: ldr r0, [r[[R0]]]
+; CHECK: ldr r0, [r[[R0]], #4]
   %0 = tail call i8* @llvm.returnaddress(i32 2)
   ret i8* %0
 }