Index: llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -587,7 +587,7 @@
 static MachineBasicBlock::iterator convertCalleeSaveRestoreToSPPrePostIncDec(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
     const DebugLoc &DL, const TargetInstrInfo *TII, int CSStackSizeInc,
-    bool NeedsWinCFI, bool InProlog = true) {
+    bool NeedsWinCFI, bool *HasWinCFI, bool InProlog = true) {
   // Ignore instructions that do not operate on SP, i.e. shadow call stack
   // instructions and associated CFI instruction.
   while (MBBI->getOpcode() == AArch64::STRXpost ||
@@ -673,9 +673,11 @@
   MIB.setMemRefs(MBBI->memoperands());
 
   // Generate a new SEH code that corresponds to the new instruction.
-  if (NeedsWinCFI)
+  if (NeedsWinCFI) {
+    *HasWinCFI = true;
     InsertSEH(*MIB, *TII,
               InProlog ? MachineInstr::FrameSetup : MachineInstr::FrameDestroy);
+  }
 
   return std::prev(MBB.erase(MBBI));
 }
@@ -684,7 +686,8 @@
 // combined SP bump by adding the local stack size to the stack offsets.
 static void fixupCalleeSaveRestoreStackOffset(MachineInstr &MI,
                                               unsigned LocalStackSize,
-                                              bool NeedsWinCFI) {
+                                              bool NeedsWinCFI,
+                                              bool *HasWinCFI) {
   if (AArch64InstrInfo::isSEHInstruction(MI))
     return;
 
@@ -731,6 +734,7 @@
   OffsetOpnd.setImm(OffsetOpnd.getImm() + LocalStackSize / Scale);
 
   if (NeedsWinCFI) {
+    *HasWinCFI = true;
     auto MBBI = std::next(MachineBasicBlock::iterator(MI));
     assert(MBBI != MI.getParent()->end() && "Expecting a valid instruction");
     assert(AArch64InstrInfo::isSEHInstruction(*MBBI) &&
@@ -802,7 +806,9 @@
                          !MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
   bool HasFP = hasFP(MF);
   bool NeedsWinCFI = needsWinCFI(MF);
-  MF.setHasWinCFI(NeedsWinCFI);
+  bool HasWinCFI = false;
+  auto Cleanup = make_scope_exit([&]() { MF.setHasWinCFI(HasWinCFI); });
+
   bool IsFunclet = MBB.isEHFuncletEntry();
 
   // At this point, we're going to decide whether or not the function uses a
@@ -858,7 +864,7 @@
       ++NumRedZoneFunctions;
     } else {
       emitFrameOffset(MBB, MBBI, DL, AArch64::SP, AArch64::SP, -NumBytes, TII,
-                      MachineInstr::FrameSetup, false, NeedsWinCFI);
+                      MachineInstr::FrameSetup, false, NeedsWinCFI, &HasWinCFI);
       if (!NeedsWinCFI) {
         // Label used to tie together the PROLOG_LABEL and the MachineMoves.
         MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
@@ -871,9 +877,11 @@
       }
     }
 
-    if (NeedsWinCFI)
+    if (NeedsWinCFI) {
+      HasWinCFI = true;
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
           .setMIFlag(MachineInstr::FrameSetup);
+    }
 
     return;
   }
@@ -891,11 +899,11 @@
   bool CombineSPBump = shouldCombineCSRLocalStackBump(MF, NumBytes);
   if (CombineSPBump) {
     emitFrameOffset(MBB, MBBI, DL, AArch64::SP, AArch64::SP, -NumBytes, TII,
-                    MachineInstr::FrameSetup, false, NeedsWinCFI);
+                    MachineInstr::FrameSetup, false, NeedsWinCFI, &HasWinCFI);
     NumBytes = 0;
   } else if (PrologueSaveSize != 0) {
     MBBI = convertCalleeSaveRestoreToSPPrePostIncDec(
-        MBB, MBBI, DL, TII, -PrologueSaveSize, NeedsWinCFI);
+        MBB, MBBI, DL, TII, -PrologueSaveSize, NeedsWinCFI, &HasWinCFI);
     NumBytes -= PrologueSaveSize;
   }
   assert(NumBytes >= 0 && "Negative stack allocation size!?");
@@ -907,7 +915,7 @@
   while (MBBI != End && MBBI->getFlag(MachineInstr::FrameSetup)) {
     if (CombineSPBump)
       fixupCalleeSaveRestoreStackOffset(*MBBI, AFI->getLocalStackSize(),
-                                        NeedsWinCFI);
+                                        NeedsWinCFI, &HasWinCFI);
     ++MBBI;
   }
 
@@ -915,9 +923,11 @@
   // opcodes that we needed to emit.  The FP and BP belong to the containing
   // function.
   if (IsFunclet) {
-    if (NeedsWinCFI)
+    if (NeedsWinCFI) {
+      HasWinCFI = true;
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
           .setMIFlag(MachineInstr::FrameSetup);
+    }
 
     // SEH funclets are passed the frame pointer in X1.  If the parent
     // function uses the base register, then the base register is used
@@ -946,12 +956,13 @@
     // 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, false, NeedsWinCFI);
+                    MachineInstr::FrameSetup, false, NeedsWinCFI, &HasWinCFI);
   }
 
   if (windowsRequiresStackProbe(MF, NumBytes)) {
     uint32_t NumWords = NumBytes >> 4;
     if (NeedsWinCFI) {
+      HasWinCFI = true;
       // alloc_l can hold at most 256MB, so assume that NumBytes doesn't
       // exceed this amount.  We need to move at most 2^24 - 1 into x15.
       // This is at most two instructions, MOVZ follwed by MOVK.
@@ -995,9 +1006,11 @@
           .addReg(AArch64::X17, RegState::Implicit | RegState::Define | RegState::Dead)
           .addReg(AArch64::NZCV, RegState::Implicit | RegState::Define | RegState::Dead)
           .setMIFlags(MachineInstr::FrameSetup);
-      if (NeedsWinCFI)
+      if (NeedsWinCFI) {
+        HasWinCFI = true;
         BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
             .setMIFlag(MachineInstr::FrameSetup);
+      }
       break;
     case CodeModel::Large:
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::MOVaddrEXT))
@@ -1005,9 +1018,11 @@
           .addExternalSymbol("__chkstk")
           .addExternalSymbol("__chkstk")
           .setMIFlags(MachineInstr::FrameSetup);
-      if (NeedsWinCFI)
+      if (NeedsWinCFI) {
+        HasWinCFI = true;
         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)
@@ -1016,9 +1031,11 @@
           .addReg(AArch64::X17, RegState::Implicit | RegState::Define | RegState::Dead)
           .addReg(AArch64::NZCV, RegState::Implicit | RegState::Define | RegState::Dead)
           .setMIFlags(MachineInstr::FrameSetup);
-      if (NeedsWinCFI)
+      if (NeedsWinCFI) {
+        HasWinCFI = true;
         BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
             .setMIFlag(MachineInstr::FrameSetup);
+      }
       break;
     }
 
@@ -1027,10 +1044,12 @@
         .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);
+    if (NeedsWinCFI) {
+      HasWinCFI = true;
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
+          .addImm(NumBytes)
+          .setMIFlag(MachineInstr::FrameSetup);
+    }
     NumBytes = 0;
   }
 
@@ -1050,7 +1069,7 @@
       // 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, false, NeedsWinCFI);
+                      MachineInstr::FrameSetup, false, NeedsWinCFI, &HasWinCFI);
 
     if (NeedsRealignment) {
       const unsigned Alignment = MFI.getMaxAlignment();
@@ -1073,10 +1092,12 @@
           .addReg(scratchSPReg, RegState::Kill)
           .addImm(andMaskEncoded);
       AFI->setStackRealigned(true);
-      if (NeedsWinCFI)
+      if (NeedsWinCFI) {
+        HasWinCFI = true;
         BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
             .addImm(NumBytes & andMaskEncoded)
             .setMIFlag(MachineInstr::FrameSetup);
+      }
     }
   }
 
@@ -1090,16 +1111,19 @@
   if (RegInfo->hasBasePointer(MF)) {
     TII->copyPhysReg(MBB, MBBI, DL, RegInfo->getBaseRegister(), AArch64::SP,
                      false);
-    if (NeedsWinCFI)
+    if (NeedsWinCFI) {
+      HasWinCFI = true;
       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)
+  if (NeedsWinCFI && HasWinCFI) {
     BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_PrologEnd))
         .setMIFlag(MachineInstr::FrameSetup);
+  }
 
   if (needsFrameMoves) {
     const DataLayout &TD = MF.getDataLayout();
@@ -1243,7 +1267,12 @@
   DebugLoc DL;
   bool IsTailCallReturn = false;
   bool NeedsWinCFI = needsWinCFI(MF);
+  bool HasWinCFI = false;
   bool IsFunclet = false;
+  auto WinCFI = make_scope_exit([&]() {
+    if (!MF.hasWinCFI())
+      MF.setHasWinCFI(HasWinCFI);
+  });
 
   if (MBB.end() != MBBI) {
     DL = MBBI->getDebugLoc();
@@ -1338,7 +1367,7 @@
     // If the offset is 0, convert it to a post-index ldp.
     if (OffsetOp.getImm() == 0)
       convertCalleeSaveRestoreToSPPrePostIncDec(
-          MBB, Pop, DL, TII, PrologueSaveSize, NeedsWinCFI, false);
+          MBB, Pop, DL, TII, PrologueSaveSize, NeedsWinCFI, &HasWinCFI, 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
@@ -1360,19 +1389,21 @@
       break;
     } else if (CombineSPBump)
       fixupCalleeSaveRestoreStackOffset(*LastPopI, AFI->getLocalStackSize(),
-                                        NeedsWinCFI);
+                                        NeedsWinCFI, &HasWinCFI);
   }
 
-  if (NeedsWinCFI)
+  if (NeedsWinCFI) {
+    HasWinCFI = true;
     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,
-                    false, NeedsWinCFI);
-    if (NeedsWinCFI)
+                    false, NeedsWinCFI, &HasWinCFI);
+    if (NeedsWinCFI && HasWinCFI)
       BuildMI(MBB, MBB.getFirstTerminator(), DL,
               TII->get(AArch64::SEH_EpilogEnd))
           .setMIFlag(MachineInstr::FrameDestroy);
@@ -1404,12 +1435,14 @@
 
     emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
                     StackRestoreBytes, TII, MachineInstr::FrameDestroy, false,
-                    NeedsWinCFI);
+                    NeedsWinCFI, &HasWinCFI);
     if (Done) {
-      if (NeedsWinCFI)
+      if (NeedsWinCFI) {
+        HasWinCFI = true;
         BuildMI(MBB, MBB.getFirstTerminator(), DL,
                 TII->get(AArch64::SEH_EpilogEnd))
             .setMIFlag(MachineInstr::FrameDestroy);
+      }
       return;
     }
 
@@ -1448,11 +1481,13 @@
 
     emitFrameOffset(MBB, FirstSPPopI, DL, AArch64::SP, AArch64::SP,
                     AfterCSRPopSize, TII, MachineInstr::FrameDestroy, false,
-                    NeedsWinCFI);
+                    NeedsWinCFI, &HasWinCFI);
   }
-  if (NeedsWinCFI)
+  if (NeedsWinCFI && HasWinCFI)
     BuildMI(MBB, MBB.getFirstTerminator(), DL, TII->get(AArch64::SEH_EpilogEnd))
         .setMIFlag(MachineInstr::FrameDestroy);
+
+  MF.setHasWinCFI(HasWinCFI);
 }
 
 /// getFrameIndexReference - Provide a base+offset reference to an FI slot for
Index: llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.h
@@ -293,7 +293,8 @@
                      const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                      int Offset, const TargetInstrInfo *TII,
                      MachineInstr::MIFlag = MachineInstr::NoFlags,
-                     bool SetNZCV = false,  bool NeedsWinCFI = false);
+                     bool SetNZCV = false, bool NeedsWinCFI = false,
+                     bool *HasWinCFI = nullptr);
 
 /// rewriteAArch64FrameIndex - Rewrite MI to access 'Offset' bytes from the
 /// FP. Return false if the offset could not be handled directly in MI, and
Index: llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -2959,7 +2959,7 @@
                            unsigned DestReg, unsigned SrcReg, int Offset,
                            const TargetInstrInfo *TII,
                            MachineInstr::MIFlag Flag, bool SetNZCV,
-                           bool NeedsWinCFI) {
+                           bool NeedsWinCFI, bool *HasWinCFI) {
   if (DestReg == SrcReg && Offset == 0)
     return;
 
@@ -3004,10 +3004,13 @@
         .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);
+    if (NeedsWinCFI && SrcReg == AArch64::SP && DestReg == AArch64::SP) {
+      if (HasWinCFI)
+        *HasWinCFI = true;
+      BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
+          .addImm(ThisVal)
+          .setMIFlag(Flag);
+    }
 
     SrcReg = DestReg;
     Offset -= ThisVal;
@@ -3023,6 +3026,8 @@
   if (NeedsWinCFI) {
     if ((DestReg == AArch64::FP && SrcReg == AArch64::SP) ||
         (SrcReg == AArch64::FP && DestReg == AArch64::SP)) {
+      if (HasWinCFI)
+        *HasWinCFI = true;
       if (Offset == 0)
         BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_SetFP)).
                 setMIFlag(Flag);
@@ -3030,6 +3035,8 @@
         BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_AddFP)).
                 addImm(Offset).setMIFlag(Flag);
     } else if (DestReg == AArch64::SP) {
+      if (HasWinCFI)
+        *HasWinCFI = true;
       BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc)).
               addImm(Offset).setMIFlag(Flag);
     }
Index: llvm/trunk/test/CodeGen/AArch64/win64-nocfi.ll
===================================================================
--- llvm/trunk/test/CodeGen/AArch64/win64-nocfi.ll
+++ llvm/trunk/test/CodeGen/AArch64/win64-nocfi.ll
@@ -0,0 +1,13 @@
+; RUN: llc < %s -mtriple=aarch64-pc-windows-msvc | FileCheck %s
+
+define dso_local void @"?f@@YAXXZ"() nounwind sspstrong uwtable {
+; CHECK-LABEL: f@@YAXXZ
+; CHECK-NOT: .seh_proc
+; CHECK-NOT: .seh_handlerdata
+; CHECK-NOT: .seh_endproc
+entry:
+  call void @llvm.trap()
+  ret void
+}
+
+declare void @llvm.trap() noreturn nounwind