Index: lib/Target/AArch64/AArch64CallingConvention.td
===================================================================
--- lib/Target/AArch64/AArch64CallingConvention.td
+++ lib/Target/AArch64/AArch64CallingConvention.td
@@ -288,6 +288,14 @@
                                            D8,  D9,  D10, D11,
                                            D12, D13, D14, D15)>;
 
+// Win64 has unwinding codes for an (FP,LR) pair, save_fplr and save_fplr_x.
+// We put FP before LR, so that frame lowering logic generates (FP,LR) pairs,
+// and not (LR,FP) pairs.
+def CSR_Win_AArch64_AAPCS : CalleeSavedRegs<(add FP, LR, X19, X20, X21, X22,
+                                               X23, X24, X25, X26, X27, X28,
+                                               D8, D9, D10, D11,
+                                               D12, D13, D14, D15)>;
+
 // AArch64 PCS for vector functions (VPCS)
 // must (additionally) preserve full Q8-Q23 registers
 def CSR_AArch64_AAVPCS : CalleeSavedRegs<(add LR, FP, X19, X20, X21, X22,
Index: lib/Target/AArch64/AArch64FrameLowering.cpp
===================================================================
--- lib/Target/AArch64/AArch64FrameLowering.cpp
+++ lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -115,11 +115,13 @@
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugLoc.h"
 #include "llvm/IR/Function.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -434,12 +436,155 @@
   return true;
 }
 
+// Given a load or a store instruction, generate an appropriate unwinding SEH
+// code on Windows.
+static MachineBasicBlock::iterator InsertSEH(MachineBasicBlock::iterator MBBI,
+                                             const TargetInstrInfo &TII,
+                                             MachineInstr::MIFlag Flag) {
+  unsigned Opc = MBBI->getOpcode();
+  MachineBasicBlock *MBB = MBBI->getParent();
+  MachineFunction &MF = *MBB->getParent();
+  DebugLoc DL = MBBI->getDebugLoc();
+  unsigned ImmIdx = MBBI->getNumOperands() - 1;
+  int Imm = MBBI->getOperand(ImmIdx).getImm();
+  MachineInstrBuilder MIB;
+  const AArch64Subtarget &Subtarget = MF.getSubtarget<AArch64Subtarget>();
+  const AArch64RegisterInfo *RegInfo = Subtarget.getRegisterInfo();
+
+  switch (Opc) {
+  default:
+    assert(false && "No SEH Opcode for this instruction");
+  case AArch64::LDPDpost:
+    Imm = -Imm;
+    LLVM_FALLTHROUGH;
+  case AArch64::STPDpre: {
+    unsigned Reg0 = RegInfo->getSEHRegNum(MBBI->getOperand(1).getReg());
+    unsigned Reg1 = RegInfo->getSEHRegNum(MBBI->getOperand(2).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFRegP_X))
+              .addImm(Reg0)
+              .addImm(Reg1)
+              .addImm(Imm * 8)
+              .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::LDPXpost:
+    Imm = -Imm;
+    LLVM_FALLTHROUGH;
+  case AArch64::STPXpre: {
+    unsigned Reg0 = MBBI->getOperand(1).getReg();
+    unsigned Reg1 = MBBI->getOperand(2).getReg();
+    if (Reg0 == AArch64::FP && Reg1 == AArch64::LR)
+      MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFPLR_X))
+                .addImm(Imm * 8)
+                .setMIFlag(Flag);
+    else
+      MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveRegP_X))
+                .addImm(RegInfo->getSEHRegNum(Reg0))
+                .addImm(RegInfo->getSEHRegNum(Reg1))
+                .addImm(Imm * 8)
+                .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::LDRDpost:
+    Imm = -Imm;
+    LLVM_FALLTHROUGH;
+  case AArch64::STRDpre: {
+    unsigned Reg = RegInfo->getSEHRegNum(MBBI->getOperand(1).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFReg_X))
+              .addImm(Reg)
+              .addImm(Imm)
+              .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::LDRXpost:
+    Imm = -Imm;
+    LLVM_FALLTHROUGH;
+  case AArch64::STRXpre: {
+    unsigned Reg =  RegInfo->getSEHRegNum(MBBI->getOperand(1).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveReg_X))
+              .addImm(Reg)
+              .addImm(Imm)
+              .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::STPDi:
+  case AArch64::LDPDi: {
+    unsigned Reg0 =  RegInfo->getSEHRegNum(MBBI->getOperand(0).getReg());
+    unsigned Reg1 =  RegInfo->getSEHRegNum(MBBI->getOperand(1).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFRegP))
+              .addImm(Reg0)
+              .addImm(Reg1)
+              .addImm(Imm * 8)
+              .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::STPXi:
+  case AArch64::LDPXi: {
+    unsigned Reg0 = MBBI->getOperand(0).getReg();
+    unsigned Reg1 = MBBI->getOperand(1).getReg();
+    if (Reg0 == AArch64::FP && Reg1 == AArch64::LR)
+      MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFPLR))
+                .addImm(Imm * 8)
+                .setMIFlag(Flag);
+    else
+      MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveRegP))
+                .addImm(RegInfo->getSEHRegNum(Reg0))
+                .addImm(RegInfo->getSEHRegNum(Reg1))
+                .addImm(Imm * 8)
+                .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::STRXui:
+  case AArch64::LDRXui: {
+    int Reg = RegInfo->getSEHRegNum(MBBI->getOperand(0).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveReg))
+              .addImm(Reg)
+              .addImm(Imm * 8)
+              .setMIFlag(Flag);
+    break;
+  }
+  case AArch64::STRDui:
+  case AArch64::LDRDui: {
+    unsigned Reg = RegInfo->getSEHRegNum(MBBI->getOperand(0).getReg());
+    MIB = BuildMI(MF, DL, TII.get(AArch64::SEH_SaveFReg))
+              .addImm(Reg)
+              .addImm(Imm * 8)
+              .setMIFlag(Flag);
+    break;
+  }
+  }
+  auto I = MBB->insertAfter(MBBI, MIB);
+  return I;
+}
+
+// Fix up the SEH opcode associated with the save/restore instruction.
+static void fixupSEHOpcode(MachineBasicBlock::iterator MBBI,
+                           unsigned LocalStackSize) {
+  MachineOperand *ImmOpnd = nullptr;
+  unsigned ImmIdx = MBBI->getNumOperands() - 1;
+  switch (MBBI->getOpcode()) {
+  default:
+    assert(false && "Fix the offset in the SEH instruction");
+    break;
+  case AArch64::SEH_SaveFPLR:
+  case AArch64::SEH_SaveRegP:
+  case AArch64::SEH_SaveReg:
+  case AArch64::SEH_SaveFRegP:
+  case AArch64::SEH_SaveFReg:
+    ImmOpnd = &MBBI->getOperand(ImmIdx);
+    break;
+  }
+  if (ImmOpnd)
+    ImmOpnd->setImm(ImmOpnd->getImm() + LocalStackSize);
+}
+
 // Convert callee-save register save/restore instruction to do stack pointer
 // decrement/increment to allocate/deallocate the callee-save stack area by
 // converting store/load to use pre/post increment version.
 static MachineBasicBlock::iterator convertCalleeSaveRestoreToSPPrePostIncDec(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
-    const DebugLoc &DL, const TargetInstrInfo *TII, int CSStackSizeInc) {
+    const DebugLoc &DL, const TargetInstrInfo *TII, int CSStackSizeInc,
+    bool NeedsWinCFI, bool InProlog = true) {
   // Ignore instructions that do not operate on SP, i.e. shadow call stack
   // instructions.
   while (MBBI->getOpcode() == AArch64::STRXpost ||
@@ -447,7 +592,6 @@
     assert(MBBI->getOperand(0).getReg() != AArch64::SP);
     ++MBBI;
   }
-
   unsigned NewOpc;
   int Scale = 1;
   switch (MBBI->getOpcode()) {
@@ -496,6 +640,12 @@
     NewOpc = AArch64::LDRQpost;
     break;
   }
+  // Get rid of the SEH code associated with the old instruction.
+  if (NeedsWinCFI) {
+    auto SEH = std::next(MBBI);
+    if (AArch64InstrInfo::isSEHInstruction(*SEH))
+      SEH->eraseFromParent();
+  }
 
   MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(NewOpc));
   MIB.addReg(AArch64::SP, RegState::Define);
@@ -517,13 +667,22 @@
   MIB.setMIFlags(MBBI->getFlags());
   MIB.setMemRefs(MBBI->memoperands());
 
+  // Generate a new SEH code that corresponds to the new instruction.
+  if (NeedsWinCFI)
+    InsertSEH(*MIB, *TII,
+              InProlog ? MachineInstr::FrameSetup : MachineInstr::FrameDestroy);
+
   return std::prev(MBB.erase(MBBI));
 }
 
 // Fixup callee-save register save/restore instructions to take into account
 // combined SP bump by adding the local stack size to the stack offsets.
 static void fixupCalleeSaveRestoreStackOffset(MachineInstr &MI,
-                                              unsigned LocalStackSize) {
+                                              unsigned LocalStackSize,
+                                              bool NeedsWinCFI) {
+  if (AArch64InstrInfo::isSEHInstruction(MI))
+    return;
+
   unsigned Opc = MI.getOpcode();
 
   // Ignore instructions that do not operate on SP, i.e. shadow call stack
@@ -563,6 +722,14 @@
   // All generated opcodes have scaled offsets.
   assert(LocalStackSize % Scale == 0);
   OffsetOpnd.setImm(OffsetOpnd.getImm() + LocalStackSize / Scale);
+
+  if (NeedsWinCFI) {
+    auto MBBI = std::next(MachineBasicBlock::iterator(MI));
+    assert(MBBI != MI.getParent()->end() && "Expecting a valid instruction");
+    assert(AArch64InstrInfo::isSEHInstruction(*MBBI) &&
+           "Expecting a SEH instruction");
+    fixupSEHOpcode(MBBI, LocalStackSize);
+  }
 }
 
 static void adaptForLdStOpt(MachineBasicBlock &MBB,
@@ -607,9 +774,12 @@
   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
   MachineModuleInfo &MMI = MF.getMMI();
   AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
-  bool needsFrameMoves = MMI.hasDebugInfo() || F.needsUnwindTableEntry();
+  bool needsFrameMoves = (MMI.hasDebugInfo() || F.needsUnwindTableEntry()) &&
+                         !MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
   bool HasFP = hasFP(MF);
-
+  bool NeedsWinCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+                     F.needsUnwindTableEntry();
+  MF.setHasWinCFI(NeedsWinCFI);
   // At this point, we're going to decide whether or not the function uses a
   // redzone. In most cases, the function doesn't have a redzone so let's
   // assume that's false and set it to true in the case that there's a redzone.
@@ -632,10 +802,8 @@
   int NumBytes = (int)MFI.getStackSize();
   if (!AFI->hasStackFrame() && !windowsRequiresStackProbe(MF, NumBytes)) {
     assert(!HasFP && "unexpected function without stack frame but with FP");
-
     // All of the stack allocation is for locals.
     AFI->setLocalStackSize(NumBytes);
-
     if (!NumBytes)
       return;
     // REDZONE: If the stack size is less than 128 bytes, we don't need
@@ -645,17 +813,23 @@
       ++NumRedZoneFunctions;
     } else {
       emitFrameOffset(MBB, MBBI, DL, AArch64::SP, AArch64::SP, -NumBytes, TII,
-                      MachineInstr::FrameSetup);
-
-      // Label used to tie together the PROLOG_LABEL and the MachineMoves.
-      MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
-      // Encode the stack size of the leaf function.
-      unsigned CFIIndex = MF.addFrameInst(
-          MCCFIInstruction::createDefCfaOffset(FrameLabel, -NumBytes));
-      BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex)
-          .setMIFlags(MachineInstr::FrameSetup);
+                      MachineInstr::FrameSetup, false, NeedsWinCFI);
+      if (!NeedsWinCFI) {
+        // Label used to tie together the PROLOG_LABEL and the MachineMoves.
+        MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
+        // Encode the stack size of the leaf function.
+        unsigned CFIIndex = MF.addFrameInst(
+            MCCFIInstruction::createDefCfaOffset(FrameLabel, -NumBytes));
+        BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
+            .addCFIIndex(CFIIndex)
+            .setMIFlags(MachineInstr::FrameSetup);
+      }
     }
+
+    if (NeedsWinCFI)
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
+          .setMIFlag(MachineInstr::FrameSetup);
+
     return;
   }
 
@@ -666,15 +840,14 @@
   auto PrologueSaveSize = AFI->getCalleeSavedStackSize() + FixedObject;
   // All of the remaining stack allocations are for locals.
   AFI->setLocalStackSize(NumBytes - PrologueSaveSize);
-
   bool CombineSPBump = shouldCombineCSRLocalStackBump(MF, NumBytes);
   if (CombineSPBump) {
     emitFrameOffset(MBB, MBBI, DL, AArch64::SP, AArch64::SP, -NumBytes, TII,
-                    MachineInstr::FrameSetup);
+                    MachineInstr::FrameSetup, false, NeedsWinCFI);
     NumBytes = 0;
   } else if (PrologueSaveSize != 0) {
-    MBBI = convertCalleeSaveRestoreToSPPrePostIncDec(MBB, MBBI, DL, TII,
-                                                     -PrologueSaveSize);
+    MBBI = convertCalleeSaveRestoreToSPPrePostIncDec(
+        MBB, MBBI, DL, TII, -PrologueSaveSize, NeedsWinCFI);
     NumBytes -= PrologueSaveSize;
   }
   assert(NumBytes >= 0 && "Negative stack allocation size!?");
@@ -685,9 +858,11 @@
   MachineBasicBlock::iterator End = MBB.end();
   while (MBBI != End && MBBI->getFlag(MachineInstr::FrameSetup)) {
     if (CombineSPBump)
-      fixupCalleeSaveRestoreStackOffset(*MBBI, AFI->getLocalStackSize());
+      fixupCalleeSaveRestoreStackOffset(*MBBI, AFI->getLocalStackSize(),
+                                        NeedsWinCFI);
     ++MBBI;
   }
+
   if (HasFP) {
     // Only set up FP if we actually need to. Frame pointer is fp =
     // sp - fixedobject - 16.
@@ -700,7 +875,7 @@
     // Note: All stores of callee-saved registers are marked as "FrameSetup".
     // This code marks the instruction(s) that set the FP also.
     emitFrameOffset(MBB, MBBI, DL, AArch64::FP, AArch64::SP, FPOffset, TII,
-                    MachineInstr::FrameSetup);
+                    MachineInstr::FrameSetup, false, NeedsWinCFI);
   }
 
   if (windowsRequiresStackProbe(MF, NumBytes)) {
@@ -709,6 +884,9 @@
     BuildMI(MBB, MBBI, DL, TII->get(AArch64::MOVi64imm), AArch64::X15)
         .addImm(NumWords)
         .setMIFlags(MachineInstr::FrameSetup);
+    if (NeedsWinCFI)
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
+          .setMIFlag(MachineInstr::FrameSetup);
 
     switch (MF.getTarget().getCodeModel()) {
     case CodeModel::Tiny:
@@ -719,6 +897,9 @@
           .addExternalSymbol("__chkstk")
           .addReg(AArch64::X15, RegState::Implicit)
           .setMIFlags(MachineInstr::FrameSetup);
+      if (NeedsWinCFI)
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
+            .setMIFlag(MachineInstr::FrameSetup);
       break;
     case CodeModel::Large:
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::MOVaddrEXT))
@@ -726,11 +907,17 @@
           .addExternalSymbol("__chkstk")
           .addExternalSymbol("__chkstk")
           .setMIFlags(MachineInstr::FrameSetup);
+      if (NeedsWinCFI)
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
+            .setMIFlag(MachineInstr::FrameSetup);
 
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::BLR))
           .addReg(AArch64::X16, RegState::Kill)
           .addReg(AArch64::X15, RegState::Implicit | RegState::Define)
           .setMIFlags(MachineInstr::FrameSetup);
+      if (NeedsWinCFI)
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
+            .setMIFlag(MachineInstr::FrameSetup);
       break;
     }
 
@@ -739,6 +926,10 @@
         .addReg(AArch64::X15, RegState::Kill)
         .addImm(AArch64_AM::getArithExtendImm(AArch64_AM::UXTX, 4))
         .setMIFlags(MachineInstr::FrameSetup);
+    if (NeedsWinCFI)
+       BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
+            .addImm(NumBytes)
+            .setMIFlag(MachineInstr::FrameSetup);
     NumBytes = 0;
   }
 
@@ -758,7 +949,7 @@
       // the correct value here, as NumBytes also includes padding bytes,
       // which shouldn't be counted here.
       emitFrameOffset(MBB, MBBI, DL, scratchSPReg, AArch64::SP, -NumBytes, TII,
-                      MachineInstr::FrameSetup);
+                      MachineInstr::FrameSetup, false, NeedsWinCFI);
 
     if (NeedsRealignment) {
       const unsigned Alignment = MFI.getMaxAlignment();
@@ -781,6 +972,10 @@
           .addReg(scratchSPReg, RegState::Kill)
           .addImm(andMaskEncoded);
       AFI->setStackRealigned(true);
+      if (NeedsWinCFI)
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
+            .addImm(NumBytes & andMaskEncoded)
+            .setMIFlag(MachineInstr::FrameSetup);
     }
   }
 
@@ -794,8 +989,17 @@
   if (RegInfo->hasBasePointer(MF)) {
     TII->copyPhysReg(MBB, MBBI, DL, RegInfo->getBaseRegister(), AArch64::SP,
                      false);
+    if (NeedsWinCFI)
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
+          .setMIFlag(MachineInstr::FrameSetup);
   }
 
+  // The very last FrameSetup instruction indicates the end of prologue. Emit a
+  // SEH opcode indicating the prologue end.
+  if (NeedsWinCFI)
+    BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
+        .setMIFlag(MachineInstr::FrameSetup);
+
   if (needsFrameMoves) {
     const DataLayout &TD = MF.getDataLayout();
     const int StackGrowth = -TD.getPointerSize(0);
@@ -923,6 +1127,9 @@
   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
   DebugLoc DL;
   bool IsTailCallReturn = false;
+  bool NeedsWinCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+                     MF.getFunction().needsUnwindTableEntry();
+
   if (MBB.end() != MBBI) {
     DL = MBBI->getDebugLoc();
     unsigned RetOpcode = MBBI->getOpcode();
@@ -930,8 +1137,9 @@
                        RetOpcode == AArch64::TCRETURNri ||
                        RetOpcode == AArch64::TCRETURNriBTI;
   }
+
   int NumBytes = MFI.getStackSize();
-  const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
+  AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
 
   // All calls are tail calls in GHC calling conv, and functions have no
   // prologue/epilogue.
@@ -996,14 +1204,16 @@
 
   if (!CombineSPBump && PrologueSaveSize != 0) {
     MachineBasicBlock::iterator Pop = std::prev(MBB.getFirstTerminator());
+    while (AArch64InstrInfo::isSEHInstruction(*Pop))
+      Pop = std::prev(Pop);
     // Converting the last ldp to a post-index ldp is valid only if the last
     // ldp's offset is 0.
     const MachineOperand &OffsetOp = Pop->getOperand(Pop->getNumOperands() - 1);
     // If the offset is 0, convert it to a post-index ldp.
-    if (OffsetOp.getImm() == 0) {
-      convertCalleeSaveRestoreToSPPrePostIncDec(MBB, Pop, DL, TII,
-                                                PrologueSaveSize);
-    } else {
+    if (OffsetOp.getImm() == 0)
+      convertCalleeSaveRestoreToSPPrePostIncDec(
+          MBB, Pop, DL, TII, PrologueSaveSize, NeedsWinCFI, false);
+    else {
       // If not, make sure to emit an add after the last ldp.
       // We're doing this by transfering the size to be restored from the
       // adjustment *before* the CSR pops to the adjustment *after* the CSR
@@ -1023,14 +1233,23 @@
       ++LastPopI;
       break;
     } else if (CombineSPBump)
-      fixupCalleeSaveRestoreStackOffset(*LastPopI, AFI->getLocalStackSize());
+      fixupCalleeSaveRestoreStackOffset(*LastPopI, AFI->getLocalStackSize(),
+                                        NeedsWinCFI);
   }
 
+  if (NeedsWinCFI)
+    BuildMI(MBB, LastPopI, DL, TII->get(AArch64::SEH_EpilogStart))
+        .setMIFlag(MachineInstr::FrameDestroy);
+
   // If there is a single SP update, insert it before the ret and we're done.
   if (CombineSPBump) {
     emitFrameOffset(MBB, MBB.getFirstTerminator(), DL, AArch64::SP, AArch64::SP,
-                    NumBytes + AfterCSRPopSize, TII,
-                    MachineInstr::FrameDestroy);
+                    NumBytes + AfterCSRPopSize, TII, MachineInstr::FrameDestroy,
+                    false, NeedsWinCFI);
+    if (NeedsWinCFI)
+      BuildMI(MBB, MBB.getFirstTerminator(), DL,
+              TII->get(AArch64::SEH_EpilogEnd))
+          .setMIFlag(MachineInstr::FrameDestroy);
     return;
   }
 
@@ -1058,9 +1277,15 @@
       adaptForLdStOpt(MBB, MBB.getFirstTerminator(), LastPopI);
 
     emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
-                    StackRestoreBytes, TII, MachineInstr::FrameDestroy);
-    if (Done)
+                    StackRestoreBytes, TII, MachineInstr::FrameDestroy, false,
+                    NeedsWinCFI);
+    if (Done) {
+      if (NeedsWinCFI)
+        BuildMI(MBB, MBB.getFirstTerminator(), DL,
+                TII->get(AArch64::SEH_EpilogEnd))
+            .setMIFlag(MachineInstr::FrameDestroy);
       return;
+    }
 
     NumBytes = 0;
   }
@@ -1072,10 +1297,10 @@
   if (MFI.hasVarSizedObjects() || AFI->isStackRealigned())
     emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::FP,
                     -AFI->getCalleeSavedStackSize() + 16, TII,
-                    MachineInstr::FrameDestroy);
+                    MachineInstr::FrameDestroy, false, NeedsWinCFI);
   else if (NumBytes)
     emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP, NumBytes, TII,
-                    MachineInstr::FrameDestroy);
+                    MachineInstr::FrameDestroy, false, NeedsWinCFI);
 
   // This must be placed after the callee-save restore code because that code
   // assumes the SP is at the same location as it was after the callee-save save
@@ -1096,8 +1321,12 @@
     adaptForLdStOpt(MBB, FirstSPPopI, LastPopI);
 
     emitFrameOffset(MBB, FirstSPPopI, DL, AArch64::SP, AArch64::SP,
-                    AfterCSRPopSize, TII, MachineInstr::FrameDestroy);
+                    AfterCSRPopSize, TII, MachineInstr::FrameDestroy, false,
+                    NeedsWinCFI);
   }
+  if (NeedsWinCFI)
+    BuildMI(MBB, MBB.getFirstTerminator(), DL, TII->get(AArch64::SEH_EpilogEnd))
+        .setMIFlag(MachineInstr::FrameDestroy);
 }
 
 /// getFrameIndexReference - Provide a base+offset reference to an FI slot for
@@ -1222,6 +1451,23 @@
            Attrs.hasAttrSomewhere(Attribute::SwiftError));
 }
 
+static bool invalidateWindowsRegisterPairing(unsigned Reg1, unsigned Reg2,
+                                             bool NeedsWinCFI) {
+  // If we are generating register pairs for a Windows function that requires
+  // EH support, then pair consecutive registers only.  There are no unwind
+  // opcodes for saves/restores of non-consectuve register pairs.
+  // The unwind opcodes are save_regp, save_regp_x, save_fregp, save_frepg_x.
+  // https://docs.microsoft.com/en-us/cpp/build/arm64-exception-handling
+
+  // TODO: LR can be paired with any register.  We don't support this yet in
+  // the MCLayer.  We need to add support for the save_lrpair unwind code.
+  if (!NeedsWinCFI)
+    return false;
+  if (Reg2 == Reg1 + 1)
+    return false;
+  return true;
+}
+
 namespace {
 
 struct RegPairInfo {
@@ -1246,6 +1492,8 @@
   if (CSI.empty())
     return;
 
+  bool NeedsWinCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+                     MF.getFunction().needsUnwindTableEntry();
   AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
   MachineFrameInfo &MFI = MF.getFrameInfo();
   CallingConv::ID CC = MF.getFunction().getCallingConv();
@@ -1258,7 +1506,11 @@
           (Count & 1) == 0) &&
          "Odd number of callee-saved regs to spill!");
   int Offset = AFI->getCalleeSavedStackSize();
-
+  // On Linux, we will have either one or zero non-paired register.  On Windows
+  // with CFI, we can have multiple unpaired registers in order to utilize the
+  // available unwind codes.  This flag assures that the alignment fixup is done
+  // only once, as intened.
+  bool FixupDone = false;
   for (unsigned i = 0; i < Count; ++i) {
     RegPairInfo RPI;
     RPI.Reg1 = CSI[i].getReg();
@@ -1272,16 +1524,17 @@
     else
       llvm_unreachable("Unsupported register class.");
 
-    // Add the next reg to the pair if it is in the same register class.
     if (i + 1 < Count) {
       unsigned NextReg = CSI[i + 1].getReg();
       switch (RPI.Type) {
       case RegPairInfo::GPR:
-        if (AArch64::GPR64RegClass.contains(NextReg))
+        if (AArch64::GPR64RegClass.contains(NextReg) &&
+            !invalidateWindowsRegisterPairing(RPI.Reg1, NextReg, NeedsWinCFI))
           RPI.Reg2 = NextReg;
         break;
       case RegPairInfo::FPR64:
-        if (AArch64::FPR64RegClass.contains(NextReg))
+        if (AArch64::FPR64RegClass.contains(NextReg) &&
+            !invalidateWindowsRegisterPairing(RPI.Reg1, NextReg, NeedsWinCFI))
           RPI.Reg2 = NextReg;
         break;
       case RegPairInfo::FPR128:
@@ -1326,8 +1579,9 @@
 
     // Round up size of non-pair to pair size if we need to pad the
     // callee-save area to ensure 16-byte alignment.
-    if (AFI->hasCalleeSaveStackFreeSpace() &&
+    if (AFI->hasCalleeSaveStackFreeSpace() && !FixupDone &&
         RPI.Type != RegPairInfo::FPR128 && !RPI.isPaired()) {
+      FixupDone = NeedsWinCFI;
       Offset -= 8;
       assert(Offset % 16 == 0);
       assert(MFI.getObjectAlignment(RPI.FrameIdx) <= 16);
@@ -1351,6 +1605,8 @@
     const TargetRegisterInfo *TRI) const {
   MachineFunction &MF = *MBB.getParent();
   const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  bool NeedsWinCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+                     MF.getFunction().needsUnwindTableEntry();
   DebugLoc DL;
   SmallVector<RegPairInfo, 8> RegPairs;
 
@@ -1368,6 +1624,10 @@
         .addImm(8)
         .setMIFlag(MachineInstr::FrameSetup);
 
+    if (NeedsWinCFI)
+      BuildMI(MBB, MI, DL, TII.get(AArch64::SEH_Nop))
+          .setMIFlag(MachineInstr::FrameSetup);
+
     // This instruction also makes x18 live-in to the entry block.
     MBB.addLiveIn(AArch64::X18);
   }
@@ -1413,6 +1673,17 @@
                if (RPI.isPaired()) dbgs() << ", " << RPI.FrameIdx + 1;
                dbgs() << ")\n");
 
+    assert((!NeedsWinCFI || !(Reg1 == AArch64::LR && Reg2 == AArch64::FP)) &&
+           "Windows unwdinding requires a consecutive (FP,LR) pair");
+    // Windows unwind codes require consecutive registers if registers are
+    // paired.  Make the switch here, so that the code below will save (x,x+1)
+    // and not (x+1,x).
+    unsigned FrameIdxReg1 = RPI.FrameIdx;
+    unsigned FrameIdxReg2 = RPI.FrameIdx + 1;
+    if (NeedsWinCFI && RPI.isPaired()) {
+      std::swap(Reg1, Reg2);
+      std::swap(FrameIdxReg1, FrameIdxReg2);
+    }
     MachineInstrBuilder MIB = BuildMI(MBB, MI, DL, TII.get(StrOpc));
     if (!MRI.isReserved(Reg1))
       MBB.addLiveIn(Reg1);
@@ -1421,7 +1692,7 @@
         MBB.addLiveIn(Reg2);
       MIB.addReg(Reg2, getPrologueDeath(MF, Reg2));
       MIB.addMemOperand(MF.getMachineMemOperand(
-          MachinePointerInfo::getFixedStack(MF, RPI.FrameIdx + 1),
+          MachinePointerInfo::getFixedStack(MF, FrameIdxReg2),
           MachineMemOperand::MOStore, Size, Align));
     }
     MIB.addReg(Reg1, getPrologueDeath(MF, Reg1))
@@ -1430,8 +1701,11 @@
                             // where factor*scale is implicit
         .setMIFlag(MachineInstr::FrameSetup);
     MIB.addMemOperand(MF.getMachineMemOperand(
-        MachinePointerInfo::getFixedStack(MF, RPI.FrameIdx),
+        MachinePointerInfo::getFixedStack(MF,FrameIdxReg1),
         MachineMemOperand::MOStore, Size, Align));
+    if (NeedsWinCFI)
+      InsertSEH(MIB, TII, MachineInstr::FrameSetup);
+
   }
   return true;
 }
@@ -1444,6 +1718,8 @@
   const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
   DebugLoc DL;
   SmallVector<RegPairInfo, 8> RegPairs;
+  bool NeedsWinCFI = MF.getTarget().getMCAsmInfo()->usesWindowsCFI() &&
+                     MF.getFunction().needsUnwindTableEntry();
 
   if (MI != MBB.end())
     DL = MI->getDebugLoc();
@@ -1489,11 +1765,20 @@
                if (RPI.isPaired()) dbgs() << ", " << RPI.FrameIdx + 1;
                dbgs() << ")\n");
 
+    // Windows unwind codes require consecutive registers if registers are
+    // paired.  Make the switch here, so that the code below will save (x,x+1)
+    // and not (x+1,x).
+    unsigned FrameIdxReg1 = RPI.FrameIdx;
+    unsigned FrameIdxReg2 = RPI.FrameIdx + 1;
+    if (NeedsWinCFI && RPI.isPaired()) {
+      std::swap(Reg1, Reg2);
+      std::swap(FrameIdxReg1, FrameIdxReg2);
+    }
     MachineInstrBuilder MIB = BuildMI(MBB, MI, DL, TII.get(LdrOpc));
     if (RPI.isPaired()) {
       MIB.addReg(Reg2, getDefRegState(true));
       MIB.addMemOperand(MF.getMachineMemOperand(
-          MachinePointerInfo::getFixedStack(MF, RPI.FrameIdx + 1),
+          MachinePointerInfo::getFixedStack(MF, FrameIdxReg2),
           MachineMemOperand::MOLoad, Size, Align));
     }
     MIB.addReg(Reg1, getDefRegState(true))
@@ -1502,10 +1787,11 @@
                             // where factor*scale is implicit
         .setMIFlag(MachineInstr::FrameDestroy);
     MIB.addMemOperand(MF.getMachineMemOperand(
-        MachinePointerInfo::getFixedStack(MF, RPI.FrameIdx),
+        MachinePointerInfo::getFixedStack(MF, FrameIdxReg1),
         MachineMemOperand::MOLoad, Size, Align));
+    if (NeedsWinCFI)
+      InsertSEH(MIB, TII, MachineInstr::FrameDestroy);
   };
-
   if (ReverseCSRRestoreSeq)
     for (const RegPairInfo &RPI : reverse(RegPairs))
       EmitMI(RPI);
Index: lib/Target/AArch64/AArch64InstrInfo.h
===================================================================
--- lib/Target/AArch64/AArch64InstrInfo.h
+++ lib/Target/AArch64/AArch64InstrInfo.h
@@ -262,6 +262,9 @@
   /// Returns true if the instruction has a shift by immediate that can be
   /// executed in one cycle less.
   bool isFalkorShiftExtFast(const MachineInstr &MI) const;
+  /// Return true if the instructions is a SEH instruciton used for unwinding
+  /// on Windows.
+  static bool isSEHInstruction(const MachineInstr &MI);
 
 private:
   /// Sets the offsets on outlined instructions in \p MBB which use SP
@@ -289,7 +292,7 @@
                      const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                      int Offset, const TargetInstrInfo *TII,
                      MachineInstr::MIFlag = MachineInstr::NoFlags,
-                     bool SetNZCV = false);
+                     bool SetNZCV = false, bool NeedsWinCFI = false);
 
 /// rewriteAArch64FrameIndex - Rewrite MI to access 'Offset' bytes from the
 /// FP. Return false if the offset could not be handled directly in MI, and
Index: lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- lib/Target/AArch64/AArch64InstrInfo.cpp
+++ lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1085,6 +1085,32 @@
   }
 }
 
+bool AArch64InstrInfo::isSEHInstruction(const MachineInstr &MI) {
+  unsigned Opc = MI.getOpcode();
+  switch (Opc) {
+    default:
+      return false;
+    case AArch64::SEH_StackAlloc:
+    case AArch64::SEH_SaveFPLR:
+    case AArch64::SEH_SaveFPLR_X:
+    case AArch64::SEH_SaveReg:
+    case AArch64::SEH_SaveReg_X:
+    case AArch64::SEH_SaveRegP:
+    case AArch64::SEH_SaveRegP_X:
+    case AArch64::SEH_SaveFReg:
+    case AArch64::SEH_SaveFReg_X:
+    case AArch64::SEH_SaveFRegP:
+    case AArch64::SEH_SaveFRegP_X:
+    case AArch64::SEH_SetFP:
+    case AArch64::SEH_AddFP:
+    case AArch64::SEH_Nop:
+    case AArch64::SEH_PrologEnd:
+    case AArch64::SEH_EpilogStart:
+    case AArch64::SEH_EpilogEnd:
+      return true;
+  }
+}
+
 bool AArch64InstrInfo::isCoalescableExtInstr(const MachineInstr &MI,
                                              unsigned &SrcReg, unsigned &DstReg,
                                              unsigned &SubIdx) const {
@@ -3026,7 +3052,8 @@
                            MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
                            unsigned DestReg, unsigned SrcReg, int Offset,
                            const TargetInstrInfo *TII,
-                           MachineInstr::MIFlag Flag, bool SetNZCV) {
+                           MachineInstr::MIFlag Flag, bool SetNZCV,
+                           bool NeedsWinCFI) {
   if (DestReg == SrcReg && Offset == 0)
     return;
 
@@ -3071,6 +3098,11 @@
         .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, ShiftSize))
         .setMIFlag(Flag);
 
+   if (NeedsWinCFI && SrcReg == AArch64::SP && DestReg == AArch64::SP)
+     BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
+         .addImm(ThisVal)
+         .setMIFlag(Flag);
+
     SrcReg = DestReg;
     Offset -= ThisVal;
     if (Offset == 0)
@@ -3081,6 +3113,21 @@
       .addImm(Offset)
       .addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0))
       .setMIFlag(Flag);
+
+  if (NeedsWinCFI) {
+    if ((DestReg == AArch64::FP && SrcReg == AArch64::SP) ||
+        (SrcReg == AArch64::FP && DestReg == AArch64::SP)) {
+      if (Offset == 0)
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_SetFP)).
+                setMIFlag(Flag);
+      else
+        BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_AddFP)).
+                addImm(Offset).setMIFlag(Flag);
+    } else if (DestReg == AArch64::SP) {
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc)).
+              addImm(Offset).setMIFlag(Flag);
+    }
+  }
 }
 
 MachineInstr *AArch64InstrInfo::foldMemoryOperandImpl(
Index: lib/Target/AArch64/AArch64RegisterInfo.h
===================================================================
--- lib/Target/AArch64/AArch64RegisterInfo.h
+++ lib/Target/AArch64/AArch64RegisterInfo.h
@@ -30,6 +30,11 @@
 public:
   AArch64RegisterInfo(const Triple &TT);
 
+  // FIXME: This should be tablegen'd like getDwarfRegNum is
+  int getSEHRegNum(unsigned i) const {
+    return getEncodingValue(i);
+  }
+
   bool isReservedReg(const MachineFunction &MF, unsigned Reg) const;
   bool isAnyArgRegReserved(const MachineFunction &MF) const;
   void emitReservedArgRegCallError(const MachineFunction &MF) const;
Index: lib/Target/AArch64/AArch64RegisterInfo.cpp
===================================================================
--- lib/Target/AArch64/AArch64RegisterInfo.cpp
+++ lib/Target/AArch64/AArch64RegisterInfo.cpp
@@ -43,6 +43,8 @@
 const MCPhysReg *
 AArch64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   assert(MF && "Invalid MachineFunction pointer.");
+  if (MF->getSubtarget<AArch64Subtarget>().isTargetWindows())
+    return CSR_Win_AArch64_AAPCS_SaveList;
   if (MF->getFunction().getCallingConv() == CallingConv::GHC)
     // GHC set of callee saved regs is empty as all those regs are
     // used for passing STG regs around
Index: test/CodeGen/AArch64/win64_vararg.ll
===================================================================
--- test/CodeGen/AArch64/win64_vararg.ll
+++ test/CodeGen/AArch64/win64_vararg.ll
@@ -104,7 +104,7 @@
 
 ; CHECK-LABEL: fp
 ; CHECK: str     x21, [sp, #-96]!
-; CHECK: stp     x20, x19, [sp, #16]
+; CHECK: stp     x19, x20, [sp, #16]
 ; CHECK: stp     x29, x30, [sp, #32]
 ; CHECK: add     x29, sp, #32
 ; CHECK: add     x8, x29, #24
@@ -125,7 +125,7 @@
 ; CHECK: mov     x4, xzr
 ; CHECK: bl      __stdio_common_vsprintf
 ; CHECK: ldp     x29, x30, [sp, #32]
-; CHECK: ldp     x20, x19, [sp, #16]
+; CHECK: ldp     x19, x20, [sp, #16]
 ; CHECK: cmp     w0, #0
 ; CHECK: csinv   w0, w0, wzr, ge
 ; CHECK: ldr     x21, [sp], #96
@@ -151,8 +151,8 @@
 
 ; CHECK-LABEL: vla
 ; CHECK: str     x23, [sp, #-112]!
-; CHECK: stp     x22, x21, [sp, #16]
-; CHECK: stp     x20, x19, [sp, #32]
+; CHECK: stp     x21, x22, [sp, #16]
+; CHECK: stp     x19, x20, [sp, #32]
 ; CHECK: stp     x29, x30, [sp, #48]
 ; CHECK: add     x29, sp, #48
 ; CHECK: add     x8, x29, #16
@@ -183,8 +183,8 @@
 ; CHECK: mov     sp, [[REG2]]
 ; CHECK: sub     sp, x29, #48
 ; CHECK: ldp     x29, x30, [sp, #48]
-; CHECK: ldp     x20, x19, [sp, #32]
-; CHECK: ldp     x22, x21, [sp, #16]
+; CHECK: ldp     x19, x20, [sp, #32]
+; CHECK: ldp     x21, x22, [sp, #16]
 ; CHECK: ldr     x23, [sp], #112
 ; CHECK: ret
 define void @vla(i32, i8*, ...) local_unnamed_addr {
@@ -211,32 +211,34 @@
 declare void @llvm.stackrestore(i8*)
 
 ; CHECK-LABEL: snprintf
-; CHECK: sub     sp,  sp, #96
-; CHECK: stp     x21, x20, [sp, #16]
-; CHECK: stp     x19, x30, [sp, #32]
-; CHECK: add     x8, sp, #56
-; CHECK: mov     x19, x2
-; CHECK: mov     x20, x1
-; CHECK: mov     x21, x0
-; CHECK: stp     x6, x7, [sp, #80]
-; CHECK: stp     x4, x5, [sp, #64]
-; CHECK: str     x3, [sp, #56]
-; CHECK: str     x8, [sp, #8]
-; CHECK: bl      __local_stdio_printf_options
-; CHECK: ldr     x8, [x0]
-; CHECK: add     x5, sp, #56
-; CHECK: mov     x1, x21
-; CHECK: mov     x2, x20
-; CHECK: orr     x0, x8, #0x2
-; CHECK: mov     x3, x19
-; CHECK: mov     x4, xzr
-; CHECK: bl      __stdio_common_vsprintf
-; CHECK: ldp     x19, x30, [sp, #32]
-; CHECK: ldp     x21, x20, [sp, #16]
-; CHECK: cmp     w0, #0
-; CHECK: csinv   w0, w0, wzr, ge
-; CHECK: add     sp, sp, #96
-; CHECK: ret
+; CHECK-DAG: sub     sp,  sp, #96
+; CHECK-DAG: str     x21, [sp, #16]
+; CHECK-DAG: stp     x19, x20, [sp, #24]
+; CHECK-DAG: str     x30, [sp, #40]
+; CHECK-DAG: add     x8, sp, #56
+; CHECK-DAG: mov     x19, x2
+; CHECK-DAG: mov     x20, x1
+; CHECK-DAG: mov     x21, x0
+; CHECK-DAG: stp     x6, x7, [sp, #80]
+; CHECK-DAG: stp     x4, x5, [sp, #64]
+; CHECK-DAG: str     x3, [sp, #56]
+; CHECK-DAG: str     x8, [sp, #8]
+; CHECK-DAG: bl      __local_stdio_printf_options
+; CHECK-DAG: ldr     x8, [x0]
+; CHECK-DAG: add     x5, sp, #56
+; CHECK-DAG: mov     x1, x21
+; CHECK-DAG: mov     x2, x20
+; CHECK-DAG: orr     x0, x8, #0x2
+; CHECK-DAG: mov     x3, x19
+; CHECK-DAG: mov     x4, xzr
+; CHECK-DAG: bl      __stdio_common_vsprintf
+; CHECK-DAG: ldr     x30, [sp, #40]
+; CHECK-DAG: ldp     x19, x20, [sp, #24]
+; CHECK-DAG: ldr     x21, [sp, #16]
+; CHECK-DAG: cmp     w0, #0
+; CHECK-DAG: csinv   w0, w0, wzr, ge
+; CHECK-DAG: add     sp, sp, #96
+; CHECK-DAG: ret
 define i32 @snprintf(i8*, i64, i8*, ...) local_unnamed_addr #5 {
   %4 = alloca i8*, align 8
   %5 = bitcast i8** %4 to i8*
Index: test/CodeGen/AArch64/wineh-frame0.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame0.mir
@@ -0,0 +1,60 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check save_regp_x, save_regp
+
+# CHECK:        early-clobber $sp = frame-setup STPXpre killed $x27, killed $x28, $sp, -10
+# CHECK-NEXT:   frame-setup SEH_SaveRegP_X 27, 28, -80
+# CHECK-NEXT:   frame-setup STPXi killed $x25, killed $x26, $sp, 2
+# CHECK-NEXT:   frame-setup SEH_SaveRegP 25, 26, 16
+# CHECK-NEXT:   frame-setup STPXi killed $x23, killed $x24, $sp, 4
+# CHECK-NEXT:   frame-setup SEH_SaveRegP 23, 24, 32
+# CHECK-NEXT:   frame-setup STPXi killed $x21, killed $x22, $sp, 6
+# CHECK-NEXT:   frame-setup SEH_SaveRegP 21, 22, 48
+# CHECK-NEXT:   frame-setup STPXi killed $x19, killed $x20, $sp, 8
+# CHECK-NEXT:   frame-setup SEH_SaveRegP 19, 20, 64
+# CHECK-NEXT:   frame-setup SEH_PrologEnd
+# CHECK:        frame-destroy SEH_EpilogStart
+# CHECK-NEXT:   $x19, $x20 = frame-destroy LDPXi $sp, 8
+# CHECK-NEXT:   frame-destroy SEH_SaveRegP 19, 20, 64
+# CHECK-NEXT:   $x21, $x22 = frame-destroy LDPXi $sp, 6
+# CHECK-NEXT:   frame-destroy SEH_SaveRegP 21, 22, 48
+# CHECK-NEXT:   $x23, $x24 = frame-destroy LDPXi $sp, 4
+# CHECK-NEXT:   frame-destroy SEH_SaveRegP 23, 24, 32
+# CHECK-NEXT:   $x25, $x26 = frame-destroy LDPXi $sp, 2
+# CHECK-NEXT:   frame-destroy SEH_SaveRegP 25, 26, 16
+# CHECK-NEXT:   early-clobber $sp, $x27, $x28 = frame-destroy LDPXpost $sp, 10
+# CHECK-NEXT:   frame-destroy SEH_SaveRegP_X 27, 28, -80
+# CHECK-NEXT:   frame-destroy SEH_EpilogEnd
+# CHECK-NEXT:   RET_ReallyLR implicit $x0
+
+...
+---
+name:            test
+alignment:       2
+tracksRegLiveness: true
+hasWinCFI: true
+liveins:
+  - { reg: '$w0' }
+frameInfo:
+  stackSize:       80
+  maxAlignment:    8
+  maxCallFrameSize: 0
+  hasOpaqueSPAdjustment: true
+stack:
+body:             |
+  bb.0.entry:
+    liveins: $x0, $x1, $x27, $x28, $x25, $x26, $x23, $x24, $x21, $x22, $x19, $x20
+    $x19 = ADDXrr $x0, killed $x1
+    $x20 = ADDXrr $x19, killed $x0
+    $x21 = ADDXrr $x20, killed $x19
+    $x22 = ADDXrr $x21, killed $x20
+    $x23 = ADDXrr $x22, killed $x21
+    $x24 = ADDXrr $x23, killed $x22
+    $x25 = ADDXrr $x24, killed $x23
+    $x26 = ADDXrr $x25, killed $x24
+    $x27 = ADDXrr $x26, killed $x25
+    $x28 = ADDXrr $x27, killed $x26
+    $x0 = COPY $x28
+    RET_ReallyLR implicit $x0
+
+...
Index: test/CodeGen/AArch64/wineh-frame1.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame1.mir
@@ -0,0 +1,94 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check save_fregp_x, save_fregp
+
+# CHECK:         early-clobber $sp = frame-setup STPDpre killed $d10, killed $d11, $sp, -14
+# CHECK-NEXT:    frame-setup SEH_SaveFRegP_X 10, 11, -112
+# CHECK-NEXT:    frame-setup STPDi killed $d8, killed $d9, $sp, 2
+# CHECK-NEXT:    frame-setup SEH_SaveFRegP 8, 9, 16
+# CHECK-NEXT:    frame-setup STPXi killed $x27, killed $x28, $sp, 4
+# CHECK-NEXT:    frame-setup SEH_SaveRegP 27, 28, 32
+# CHECK-NEXT:    frame-setup STPXi killed $x25, killed $x26, $sp, 6
+# CHECK-NEXT:    frame-setup SEH_SaveRegP 25, 26, 48
+# CHECK-NEXT:    frame-setup STPXi killed $x23, killed $x24, $sp, 8
+# CHECK-NEXT:    frame-setup SEH_SaveRegP 23, 24, 64
+# CHECK-NEXT:    frame-setup STPXi killed $x21, killed $x22, $sp, 10
+# CHECK-NEXT:    frame-setup SEH_SaveRegP 21, 22, 80
+# CHECK-NEXT:    frame-setup STPXi killed $x19, killed $x20, $sp, 12
+# CHECK-NEXT:    frame-setup SEH_SaveRegP 19, 20, 96
+# CHECK-NEXT:    frame-setup SEH_PrologEnd
+# CHECK:         frame-destroy SEH_EpilogStart
+# CHECK-NEXT:    $x19, $x20 = frame-destroy LDPXi $sp, 12
+# CHECK-NEXT:    frame-destroy SEH_SaveRegP 19, 20, 96
+# CHECK-NEXT:    $x21, $x22 = frame-destroy LDPXi $sp, 10
+# CHECK-NEXT:    frame-destroy SEH_SaveRegP 21, 22, 80
+# CHECK-NEXT:    $x23, $x24 = frame-destroy LDPXi $sp, 8
+# CHECK-NEXT:    frame-destroy SEH_SaveRegP 23, 24, 64
+# CHECK-NEXT:    $x25, $x26 = frame-destroy LDPXi $sp, 6
+# CHECK-NEXT:    frame-destroy SEH_SaveRegP 25, 26, 48
+# CHECK-NEXT:    $x27, $x28 = frame-destroy LDPXi $sp, 4
+# CHECK-NEXT:    frame-destroy SEH_SaveRegP 27, 28, 32
+# CHECK-NEXT:    $d8, $d9 = frame-destroy LDPDi $sp, 2
+# CHECK-NEXT:    frame-destroy SEH_SaveFRegP 8, 9, 16
+# CHECK-NEXT:    early-clobber $sp, $d10, $d11 = frame-destroy LDPDpost $sp, 14
+# CHECK-NEXT:    frame-destroy SEH_SaveFRegP_X 10, 11, -112
+# CHECK-NEXT:    frame-destroy SEH_EpilogEnd
+# CHECK-NEXT:    RET_ReallyLR implicit $x0
+...
+---
+name:            test
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       true
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       112
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  hasOpaqueSPAdjustment: true
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+constants:
+body:             |
+  bb.0.entry:
+    liveins: $x0, $x1, $d0, $d1, $d10, $d11, $d8, $d9, $x27, $x28, $x25, $x26, $x23, $x24, $x21, $x22, $x19, $x20
+
+    $x19 = ADDXrr $x0, killed $x1
+    $d8 = FADDDrr killed $d0, $d1
+    $d9 = FADDDrr $d8, $d1
+    $d10 = FADDDrr $d9, $d8
+    $d11 = FADDDrr killed $d9, $d10
+    $x20 = ADDXrr $x19, killed $x0
+    $x21 = ADDXrr $x20, killed $x19
+    $x22 = ADDXrr $x21, killed $x20
+    $x23 = ADDXrr $x22, killed $x21
+    $x24 = ADDXrr $x23, killed $x22
+    $x25 = ADDXrr $x24, killed $x23
+    $x26 = ADDXrr $x25, killed $x24
+    $x27 = ADDXrr $x26, killed $x25
+    $x28 = ADDXrr $x27, killed $x26
+    $x0 = COPY $d11
+    $x0 = ADDXrr $x0, killed $x28
+    RET_ReallyLR implicit $x0
+
+...
Index: test/CodeGen/AArch64/wineh-frame2.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame2.mir
@@ -0,0 +1,72 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check save_freg_x, save_frep, save_reg
+
+# CHECK:       early-clobber $sp = frame-setup STRDpre killed $d12, $sp, -48
+# CHECK-NEXT:  frame-setup SEH_SaveFReg_X 12, -48
+# CHECK-NEXT:  frame-setup STPDi killed $d10, killed $d11, $sp, 1
+# CHECK-NEXT:  frame-setup SEH_SaveFRegP 10, 11, 8
+# CHECK-NEXT:  frame-setup STPDi killed $d8, killed $d9, $sp, 3
+# CHECK-NEXT:  frame-setup SEH_SaveFRegP 8, 9, 24
+# CHECK-NEXT:  frame-setup STRXui killed $x19, $sp, 5
+# CHECK-NEXT:  frame-setup SEH_SaveReg 19, 40
+# CHECK-NEXT:  frame-setup SEH_PrologEnd
+# CHECK:       frame-destroy SEH_EpilogStart
+# CHECK-NEXT:  $x19 = frame-destroy LDRXui $sp, 5
+# CHECK-NEXT:  frame-destroy SEH_SaveReg 19, 40
+# CHECK-NEXT:  $d8, $d9 = frame-destroy LDPDi $sp, 3
+# CHECK-NEXT:  frame-destroy SEH_SaveFRegP 8, 9, 24
+# CHECK-NEXT:  $d10, $d11 = frame-destroy LDPDi $sp, 1
+# CHECK-NEXT:  frame-destroy SEH_SaveFRegP 10, 11, 8
+# CHECK-NEXT:  early-clobber $sp, $d12 = frame-destroy LDRDpost $sp, 48
+# CHECK-NEXT:  frame-destroy SEH_SaveFReg_X 12, -48
+# CHECK-NEXT:  frame-destroy SEH_EpilogEnd
+# CHECK-NEXT:  RET_ReallyLR implicit $x0
+...
+---
+name:            test
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       true
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       112
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  hasOpaqueSPAdjustment: true
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+constants:
+body:             |
+  bb.0.entry:
+    liveins: $x0, $x1, $d0, $d1, $d10, $d11, $d8, $d9
+    $x19 = ADDXrr $x0, killed $x1
+    $d8 = FADDDrr killed $d0, $d1
+    $d9 = FADDDrr $d8, $d1
+    $d10 = FADDDrr $d9, $d8
+    $d11 = FADDDrr killed $d9, $d10
+    $d12 = FADDDrr $d11, killed $d11
+    $x0 = COPY $d12
+    RET_ReallyLR implicit $x0
+
+...
Index: test/CodeGen/AArch64/wineh-frame3.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame3.mir
@@ -0,0 +1,59 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check save_reg_x, save_reg
+
+# CHECK:      early-clobber $sp = frame-setup STRXpre killed $x22, $sp, -16
+# CHECK-NEXT: frame-setup SEH_SaveReg_X 22, -16
+# CHECK-NEXT: frame-setup STRXui killed $x19, $sp, 1
+# CHECK-NEXT: frame-setup SEH_SaveReg 19, 8
+# CHECK-NEXT: frame-setup SEH_PrologEnd
+# CHECK:      frame-destroy SEH_EpilogStart
+# CHECK-NEXT: $x19 = frame-destroy LDRXui $sp, 1
+# CHECK-NEXT: frame-destroy SEH_SaveReg 19, 8
+# CHECK-NEXT: early-clobber $sp, $x22 = frame-destroy LDRXpost $sp, 16
+# CHECK-NEXT: frame-destroy SEH_SaveReg_X 22, -16
+# CHECK-NEXT: frame-destroy SEH_EpilogEnd
+# CHECK-NEXT: RET_ReallyLR implicit $x0
+...
+---
+name:            test
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       true
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       112
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  hasOpaqueSPAdjustment: true
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+constants:
+body:             |
+  bb.0.entry:
+    liveins: $x0, $x1
+    $x19 = ADDXrr $x0, killed $x1
+    $x22 = ADDXrr killed $x19, $x0
+    $x0 = COPY killed $x22
+    RET_ReallyLR implicit $x0
+...
Index: test/CodeGen/AArch64/wineh-frame4.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame4.mir
@@ -0,0 +1,59 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check save_freg_x, save_freg
+
+# CHECK:       early-clobber $sp = frame-setup STRDpre killed $d10, $sp, -16
+# CHECK-NEXT:  frame-setup SEH_SaveFReg_X 10, -16
+# CHECK-NEXT:  frame-setup STRDui killed $d8, $sp, 1 :: (store 8 into %stack.0)
+# CHECK-NEXT:  frame-setup SEH_SaveFReg 8, 8
+# CHECK-NEXT:  frame-setup SEH_PrologEnd
+# CHECK:       frame-destroy SEH_EpilogStart
+# CHECK-NEXT:  $d8 = frame-destroy LDRDui $sp, 1 :: (load 8 from %stack.0)
+# CHECK-NEXT:  frame-destroy SEH_SaveFReg 8, 8
+# CHECK-NEXT:  early-clobber $sp, $d10 = frame-destroy LDRDpost $sp, 16 :: (load 8 from %stack.1)
+# CHECK-NEXT:  frame-destroy SEH_SaveFReg_X 10, -16
+# CHECK-NEXT:  frame-destroy SEH_EpilogEnd
+# CHECK-NEXT:  RET_ReallyLR implicit $x0
+...
+---
+name:            test
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       true
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       112
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  hasOpaqueSPAdjustment: true
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+constants:
+body:             |
+  bb.0.entry:
+    liveins: $d0, $d1
+    $d8 = FADDDrr $d0, killed $d1
+    $d10 = FADDDrr killed $d8, $d0
+    $x0 = COPY killed $d10
+    RET_ReallyLR implicit $x0
+...
Index: test/CodeGen/AArch64/wineh-frame5.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame5.mir
@@ -0,0 +1,135 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Check multiple epilogues, save_reg, save_reg_x.
+
+# CHECK-LABEL:   bb.0.entry:
+# CHECK:         early-clobber $sp = frame-setup STRXpre killed $x28, $sp, -32
+# CHECK-NEXT:    frame-setup SEH_SaveReg_X 28, -32
+# CHECK-NEXT:    frame-setup STRXui killed $x19, $sp, 1
+# CHECK-NEXT:    frame-setup SEH_SaveReg 19, 8
+# CHECK-NEXT:    frame-setup STRXui killed $lr, $sp, 2
+# CHECK-NEXT:    frame-setup SEH_SaveReg 30, 16
+# CHECK-NEXT:    $sp = frame-setup SUBXri $sp, 496, 0
+# CHECK-NEXT:    frame-setup SEH_StackAlloc 496
+# CHECK-NEXT:    frame-setup SEH_PrologEnd
+
+# CHECK-LABEL:   bb.1.if.then:
+# CHECK:         frame-destroy SEH_EpilogStart
+# CHECK-NEXT:    $sp = frame-destroy ADDXri $sp, 496, 0
+# CHECK-NEXT:    frame-destroy SEH_StackAlloc 496
+# CHECK-NEXT:    $lr = frame-destroy LDRXui $sp, 2
+# CHECK-NEXT:    frame-destroy SEH_SaveReg 30, 16
+# CHECK-NEXT:    $x19 = frame-destroy LDRXui $sp, 1
+# CHECK-NEXT:    frame-destroy SEH_SaveReg 19, 8
+# CHECK-NEXT:    early-clobber $sp, $x28 = frame-destroy LDRXpost $sp, 32
+# CHECK-NEXT:    frame-destroy SEH_SaveReg_X 28, -32
+# CHECK-NEXT:    frame-destroy SEH_EpilogEnd
+# CHECK-NEXT:    TCRETURNdi @"?func2@@YAHXZ", 0, csr_aarch64_aapcs, implicit $sp
+
+
+--- |
+  target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64-unknown-windows-msvc19.11.0"
+
+  define dso_local i32 @"?func@@YAHH@Z"(i32 %i) local_unnamed_addr #0 {
+  entry:
+    %B = alloca [123 x i32], align 4
+    %call = tail call i32 @"?func2@@YAHXZ"()
+    %cmp = icmp sgt i32 %i, 2
+    br i1 %cmp, label %if.then, label %if.else
+
+  if.then:                                          ; preds = %entry
+    %call1 = tail call i32 @"?func2@@YAHXZ"()
+    ret i32 %call1
+
+  if.else:                                          ; preds = %entry
+    %0 = bitcast [123 x i32]* %B to i8*
+    call void @llvm.lifetime.start.p0i8(i64 492, i8* nonnull %0) #3
+    %arraydecay7 = bitcast [123 x i32]* %B to i32*
+    %call2 = call i32 @"?func3@@YAHPEAH@Z"(i32* nonnull %arraydecay7)
+    call void @llvm.lifetime.end.p0i8(i64 492, i8* nonnull %0) #3
+    ret i32 %call2
+  }
+
+  ; Function Attrs: argmemonly nounwind
+  declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
+
+  declare dso_local i32 @"?func2@@YAHXZ"() local_unnamed_addr #2
+
+  declare dso_local i32 @"?func3@@YAHPEAH@Z"(i32*) local_unnamed_addr #2
+
+  ; Function Attrs: argmemonly nounwind
+  declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
+
+  ; Function Attrs: nounwind
+  declare void @llvm.stackprotector(i8*, i8**) #3
+
+  attributes #0 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #1 = { argmemonly nounwind }
+  attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #3 = { nounwind }
+
+...
+---
+name:            '?func@@YAHH@Z'
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    4
+  adjustsStack:    true
+  hasCalls:        true
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  492
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+  - { id: 0, name: B, type: default, offset: 0, size: 492, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -492, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+constants:
+body:             |
+  bb.0.entry:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+    liveins: $w0
+
+    renamable $w19 = COPY $w0
+    ADJCALLSTACKDOWN 0, 0, implicit-def dead $sp, implicit $sp
+    BL @"?func2@@YAHXZ", csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit-def $sp, implicit-def dead $w0
+    ADJCALLSTACKUP 0, 0, implicit-def dead $sp, implicit $sp
+    dead $wzr = SUBSWri killed renamable $w19, 3, 0, implicit-def $nzcv
+    Bcc 11, %bb.2, implicit killed $nzcv
+    B %bb.1
+
+  bb.1.if.then:
+    TCRETURNdi @"?func2@@YAHXZ", 0, csr_aarch64_aapcs, implicit $sp
+
+  bb.2.if.else:
+    ADJCALLSTACKDOWN 0, 0, implicit-def dead $sp, implicit $sp
+    $x0 = ADDXri %stack.0.B, 0, 0
+    BL @"?func3@@YAHPEAH@Z", csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit $x0, implicit-def $sp, implicit-def $w0
+    ADJCALLSTACKUP 0, 0, implicit-def dead $sp, implicit $sp
+    RET_ReallyLR implicit $w0
+
+...
Index: test/CodeGen/AArch64/wineh-frame6.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame6.mir
@@ -0,0 +1,150 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Test that stack probe results in Nop unwind codes in the prologue.  Test
+# save_fplr, save_reg_x and stack_alloc with multiple updates
+
+# CHECK:      early-clobber $sp = frame-setup STPXpre killed $fp, killed $lr, $sp, -2
+# CHECK-NEXT: frame-setup SEH_SaveFPLR_X -16
+# CHECK-NEXT: $fp = frame-setup ADDXri $sp, 0, 0
+# CHECK-NEXT: frame-setup SEH_SetFP
+# CHECK-NEXT: $sp = frame-setup SUBXri $sp, 32, 0
+# CHECK-NEXT: frame-setup SEH_StackAlloc 32
+# CHECK-NEXT: frame-setup SEH_PrologEnd
+# CHECK:      frame-destroy SEH_EpilogStart
+# CHECK-NEXT: $sp = frame-destroy ADDXri $fp, 0, 0
+# CHECK-NEXT: frame-destroy SEH_SetFP
+# CHECK-NEXT: early-clobber $sp, $fp, $lr = frame-destroy LDPXpost $sp, 2
+# CHECK-NEXT: frame-destroy SEH_SaveFPLR_X -16
+# CHECK-NEXT: frame-destroy SEH_EpilogEnd
+# CHECK-NEXT: RET_ReallyLR implicit killed $w0
+--- |
+  target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64-unknown-windows-msvc19.11.0"
+
+  ; Function Attrs: noinline optnone
+  define dso_local i32 @"?func@@YAHHHHH@Z"(i32 %n, i32 %idx, i32 %b, i32 %c) #0 {
+  entry:
+    %c.addr = alloca i32, align 4
+    %b.addr = alloca i32, align 4
+    %idx.addr = alloca i32, align 4
+    %n.addr = alloca i32, align 4
+    %a = alloca i32*, align 8
+    store i32 %c, i32* %c.addr, align 4
+    store i32 %b, i32* %b.addr, align 4
+    store i32 %idx, i32* %idx.addr, align 4
+    store i32 %n, i32* %n.addr, align 4
+    %0 = load i32, i32* %n.addr, align 4
+    %conv = sext i32 %0 to i64
+    %1 = alloca i8, i64 %conv, align 16
+    %2 = bitcast i8* %1 to i32*
+    store i32* %2, i32** %a, align 8
+    %3 = load i32*, i32** %a, align 8
+    call void @"?init@@YAXPEAH@Z"(i32* %3)
+    ret i32 0
+  }
+
+  declare dso_local void @"?init@@YAXPEAH@Z"(i32*) #1
+
+  ; Function Attrs: nounwind
+  declare void @llvm.stackprotector(i8*, i8**) #2
+
+  attributes #0 = { noinline optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #2 = { nounwind }
+
+...
+---
+name:            '?func@@YAHHHHH@Z'
+alignment:       2
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+registers:
+liveins:
+  - { reg: '$w0', virtual-reg: '' }
+  - { reg: '$w1', virtual-reg: '' }
+  - { reg: '$w2', virtual-reg: '' }
+  - { reg: '$w3', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    true
+  hasCalls:        true
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  24
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+  - { id: 0, name: c.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -4, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 1, name: b.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -8, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 2, name: idx.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -12, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 3, name: n.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -16, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 4, name: a, type: default, offset: 0, size: 8, alignment: 8,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -24, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 5, name: '', type: variable-sized, offset: 0,
+      alignment: 1, stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -24, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 6, name: '', type: spill-slot, offset: 0, size: 8, alignment: 8,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+constants:
+body:             |
+  bb.0.entry:
+    liveins: $w0, $w1, $w2, $w3
+
+    STRWui killed renamable $w3, %stack.0.c.addr, 0 :: (store 4 into %ir.c.addr)
+    STRWui killed renamable $w2, %stack.1.b.addr, 0 :: (store 4 into %ir.b.addr)
+    STRWui killed renamable $w1, %stack.2.idx.addr, 0 :: (store 4 into %ir.idx.addr)
+    STRWui killed renamable $w0, %stack.3.n.addr, 0 :: (store 4 into %ir.n.addr)
+    renamable $x8 = LDRSWui %stack.3.n.addr, 0 :: (dereferenceable load 4 from %ir.n.addr)
+    ADJCALLSTACKDOWN 0, 0, implicit-def dead $sp, implicit $sp
+    renamable $x8 = nuw ADDXri killed renamable $x8, 15, 0
+    renamable $x8 = UBFMXri killed renamable $x8, 4, 63
+    $x15 = COPY renamable $x8
+    STRXui killed $x8, %stack.6, 0 :: (store 8 into %stack.6)
+    BL &__chkstk, csr_aarch64_stackprobe_windows, implicit-def dead $lr, implicit $sp, implicit killed $x15
+    renamable $x8 = COPY $sp
+    $x15 = LDRXui %stack.6, 0 :: (load 8 from %stack.6)
+    renamable $x8 = SUBSXrs killed renamable $x8, killed renamable $x15, 4, implicit-def dead $nzcv
+    $sp = COPY renamable $x8
+    ADJCALLSTACKUP 0, 0, implicit-def dead $sp, implicit $sp
+    STRXui killed renamable $x8, %stack.4.a, 0 :: (store 8 into %ir.a)
+    renamable $x0 = LDRXui %stack.4.a, 0 :: (dereferenceable load 8 from %ir.a)
+    ADJCALLSTACKDOWN 0, 0, implicit-def dead $sp, implicit $sp
+    BL @"?init@@YAXPEAH@Z", csr_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit killed $x0, implicit-def $sp
+    ADJCALLSTACKUP 0, 0, implicit-def dead $sp, implicit $sp
+    renamable $w1 = COPY $wzr
+    $w0 = COPY killed renamable $w1
+    RET_ReallyLR implicit killed $w0
+
+...
Index: test/CodeGen/AArch64/wineh-frame7.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame7.mir
@@ -0,0 +1,187 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Test that stack probe results in Nop unwind codes in the prologue.  Test
+# save_fplr, save_reg_x and stack_alloc with multiple updates.
+
+# CHECK:      early-clobber $sp = frame-setup STRXpre killed $x28, $sp, -32
+# CHECK-NEXT: frame-setup SEH_SaveReg_X 28, -32
+# CHECK-NEXT: frame-setup STPXi killed $fp, killed $lr, $sp, 2
+# CHECK-NEXT: frame-setup SEH_SaveFPLR 16
+# CHECK-NEXT: $x15 = frame-setup MOVi64imm 187081
+# CHECK-NEXT: frame-setup SEH_Nop
+# CHECK-NEXT: frame-setup BL &__chkstk, implicit-def $lr, implicit $sp, implicit $x15
+# CHECK-NEXT: frame-setup SEH_Nop
+# CHECK-NEXT: $sp = frame-setup SUBXrx64 killed $sp, killed $x15, 28
+# CHECK-NEXT: frame-setup SEH_StackAlloc 2993296
+# CHECK-NEXT: frame-setup SEH_PrologEnd
+# CHECK:      frame-destroy SEH_EpilogStart
+# CHECK-NEXT: $sp = frame-destroy ADDXri $sp, 730, 12
+# CHECK-NEXT: frame-destroy SEH_StackAlloc 2990080
+# CHECK-NEXT: $sp = frame-destroy ADDXri $sp, 3216, 0
+# CHECK-NEXT: frame-destroy SEH_StackAlloc 3216
+# CHECK-NEXT: $fp, $lr = frame-destroy LDPXi $sp, 2
+# CHECK-NEXT: frame-destroy SEH_SaveFPLR 16
+# CHECK-NEXT: early-clobber $sp, $x28 = frame-destroy LDRXpost $sp, 32
+# CHECK-NEXT: frame-destroy SEH_SaveReg_X 28, -32
+# CHECK-NEXT: frame-destroy SEH_EpilogEnd
+# CHECK-NEXT: RET_ReallyLR implicit killed $w0
+--- |
+  target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64-unknown-windows-msvc19.11.0"
+
+  ; Function Attrs: noinline optnone
+  define dso_local i32 @"?func@@YAHH@Z"(i32 %i) #0 {
+  entry:
+    %retval = alloca i32, align 4
+    %i.addr = alloca i32, align 4
+    %A = alloca [748193 x i32], align 4
+    %a = alloca i32, align 4
+    %B = alloca [123 x i32], align 4
+    store i32 %i, i32* %i.addr, align 4
+    %0 = load i32, i32* %i.addr, align 4
+    %add = add nsw i32 %0, 2
+    store i32 %add, i32* %a, align 4
+    %call = call i32 @"?func2@@YAHXZ"()
+    %1 = load i32, i32* %i.addr, align 4
+    %cmp = icmp sgt i32 %1, 2
+    br i1 %cmp, label %if.then, label %if.else
+
+  if.then:                                          ; preds = %entry
+    %call1 = call i32 @"?func2@@YAHXZ"()
+    store i32 %call1, i32* %retval, align 4
+    br label %return
+
+  if.else:                                          ; preds = %entry
+    %arraydecay = getelementptr inbounds [123 x i32], [123 x i32]* %B, i32 0, i32 0
+    %call2 = call i32 @"?func3@@YAHPEAH@Z"(i32* %arraydecay)
+    store i32 %call2, i32* %retval, align 4
+    br label %return
+
+  return:                                           ; preds = %if.else, %if.then
+    %2 = load i32, i32* %retval, align 4
+    ret i32 %2
+  }
+
+  declare dso_local i32 @"?func2@@YAHXZ"() #1
+
+  declare dso_local i32 @"?func3@@YAHPEAH@Z"(i32*) #1
+
+  ; Function Attrs: nounwind
+  declare void @llvm.stackprotector(i8*, i8**) #2
+
+  attributes #0 = { noinline optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+  attributes #2 = { nounwind }
+
+...
+---
+name:            '?func@@YAHH@Z'
+alignment:       2
+exposesReturnsTwice: false
+legalized:       true
+regBankSelected: true
+selected:        true
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+registers:
+liveins:
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    true
+  hasCalls:        true
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  2993276
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+  - { id: 0, name: retval, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -4, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 1, name: i.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -8, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 2, name: A, type: default, offset: 0, size: 2992772, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -2992780, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 3, name: a, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -2992784, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 4, name: B, type: default, offset: 0, size: 492, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -2993276, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 5, name: '', type: spill-slot, offset: 0, size: 8, alignment: 8,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 6, name: '', type: spill-slot, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+constants:
+body:             |
+  bb.1.entry:
+    successors: %bb.2(0x40000000), %bb.3(0x40000000)
+    liveins: $w0
+
+    renamable $x8 = ADDXri %stack.1.i.addr, 0, 0
+    renamable $w9 = MOVi32imm 2
+    STRWui killed renamable $w0, renamable $x8, 0 :: (store 4 into %ir.i.addr)
+    renamable $w0 = LDRWui renamable $x8, 0 :: (load 4 from %ir.i.addr)
+    renamable $w0 = ADDWri killed renamable $w0, 2, 0
+    STRWui killed renamable $w0, %stack.3.a, 0 :: (store 4 into %ir.a)
+    ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    STRXui killed $x8, %stack.5, 0 :: (store 8 into %stack.5)
+    STRWui killed $w9, %stack.6, 0 :: (store 4 into %stack.6)
+    BL @"?func2@@YAHXZ", csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit-def $w0
+    ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    $x8 = LDRXui %stack.5, 0 :: (load 8 from %stack.5)
+    renamable $w9 = LDRWui killed renamable $x8, 0 :: (load 4 from %ir.i.addr)
+    $w10 = LDRWui %stack.6, 0 :: (load 4 from %stack.6)
+    $wzr = SUBSWrr killed renamable $w9, killed renamable $w10, implicit-def $nzcv
+    renamable $w9 = CSINCWr $wzr, $wzr, 13, implicit $nzcv
+    TBNZW killed renamable $w9, 0, %bb.2
+    B %bb.3
+
+  bb.2.if.then:
+    successors: %bb.4(0x80000000)
+
+    ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    BL @"?func2@@YAHXZ", csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit-def $w0
+    ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    $x8 = LDRXui %stack.5, 0 :: (load 8 from %stack.5)
+    STRWui killed renamable $w0, killed renamable $x8, 1 :: (store 4 into %ir.retval)
+    B %bb.4
+
+  bb.3.if.else:
+    successors: %bb.4(0x80000000)
+
+    renamable $x8 = ADDXri %stack.4.B, 0, 0
+    ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    $x0 = COPY killed renamable $x8
+    BL @"?func3@@YAHPEAH@Z", csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit killed $x0, implicit-def $w0
+    ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    $x8 = LDRXui %stack.5, 0 :: (load 8 from %stack.5)
+    STRWui killed renamable $w0, killed renamable $x8, 1 :: (store 4 into %ir.retval)
+
+  bb.4.return:
+    $x8 = LDRXui %stack.5, 0 :: (load 8 from %stack.5)
+    renamable $w0 = LDRWui killed renamable $x8, 1 :: (load 4 from %ir.retval)
+    RET_ReallyLR implicit killed $w0
+
+...
Index: test/CodeGen/AArch64/wineh-frame8.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/wineh-frame8.mir
@@ -0,0 +1,88 @@
+# RUN: llc -o - %s -mtriple=aarch64-windows -start-before=prologepilog \
+# RUN:   -stop-after=prologepilog | FileCheck %s
+# Test that the frame lowering emits correct SEH updates for the case without
+# a stack frame (e.g. no callee saved registers, no frame pointer, just locals)
+
+# CHECK:      $sp = frame-setup SUBXri $sp, 16, 0
+# CHECK-NEXT: frame-setup SEH_StackAlloc 16
+# CHECK-NEXT: frame-setup SEH_PrologEnd
+# CHECK:      frame-destroy SEH_EpilogStart
+# CHECK-NEXT: $sp = frame-destroy ADDXri $sp, 16, 0
+# CHECK-NEXT: frame-destroy SEH_StackAlloc 16
+# CHECK-NEXT: frame-destroy SEH_EpilogEnd
+# CHECK-NEXT: RET_ReallyLR implicit killed $w0
+
+--- |
+  target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64-unknown-windows-msvc19.11.0"
+
+  ; Function Attrs: noinline nounwind optnone uwtable
+  define dso_local i32 @"?func@@YAHH@Z"(i32 %a) #0 {
+  entry:
+    %a.addr = alloca i32, align 4
+    %b = alloca i32, align 4
+    store i32 %a, i32* %a.addr, align 4
+    store i32 2, i32* %b, align 4
+    %0 = load i32, i32* %b, align 4
+    %1 = load i32, i32* %a.addr, align 4
+    %add = add nsw i32 %0, %1
+    ret i32 %add
+  }
+
+  attributes #0 = { noinline nounwind optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+neon" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+...
+---
+name:            '?func@@YAHH@Z'
+alignment:       2
+exposesReturnsTwice: false
+legalized:       true
+regBankSelected: true
+selected:        true
+failedISel:      false
+tracksRegLiveness: true
+registers:
+liveins:
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    4
+  adjustsStack:    false
+  hasCalls:        false
+  stackProtector:  ''
+  maxCallFrameSize: 0
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  8
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:
+stack:
+  - { id: 0, name: a.addr, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -4, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+  - { id: 1, name: b, type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: 0, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -8, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+constants:
+body:             |
+  bb.1.entry:
+    liveins: $w0
+
+    renamable $w8 = MOVi32imm 2
+    STRWui killed renamable $w0, %stack.0.a.addr, 0 :: (store 4 into %ir.a.addr)
+    STRWui killed renamable $w8, %stack.1.b, 0 :: (store 4 into %ir.b)
+    renamable $w8 = LDRWui %stack.1.b, 0 :: (load 4 from %ir.b)
+    renamable $w0 = LDRWui %stack.0.a.addr, 0 :: (load 4 from %ir.a.addr)
+    renamable $w0 = nsw ADDWrr killed renamable $w8, killed renamable $w0
+    RET_ReallyLR implicit killed $w0
+
+...