diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.h b/llvm/lib/Target/PowerPC/PPCFrameLowering.h
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.h
@@ -21,12 +21,12 @@
 
 class PPCFrameLowering: public TargetFrameLowering {
   const PPCSubtarget &Subtarget;
-  const unsigned ReturnSaveOffset;
-  const unsigned TOCSaveOffset;
-  const unsigned FramePointerSaveOffset;
+  const uint64_t ReturnSaveOffset;
+  const uint64_t TOCSaveOffset;
+  const uint64_t FramePointerSaveOffset;
   const unsigned LinkageSize;
-  const unsigned BasePointerSaveOffset;
-  const unsigned CRSaveOffset;
+  const uint64_t BasePointerSaveOffset;
+  const uint64_t CRSaveOffset;
 
   // Map each group of one or two GPRs to corresponding VSR for spilling.
   // TODO: Use local table in methods to avoid this mutable member.
@@ -88,7 +88,7 @@
   /**
    * Determine the frame layout and update the machine function.
    */
-  unsigned determineFrameLayoutAndUpdate(MachineFunction &MF,
+  uint64_t determineFrameLayoutAndUpdate(MachineFunction &MF,
                                          bool UseEstimate = false) const;
 
   /**
@@ -96,7 +96,7 @@
    * The MachineFunction object can be const in this case as it is not
    * modified.
    */
-  unsigned determineFrameLayout(const MachineFunction &MF,
+  uint64_t determineFrameLayout(const MachineFunction &MF,
                                 bool UseEstimate = false,
                                 unsigned *NewMaxCallFrameSize = nullptr) const;
 
@@ -146,19 +146,19 @@
 
   /// getReturnSaveOffset - Return the previous frame offset to save the
   /// return address.
-  unsigned getReturnSaveOffset() const { return ReturnSaveOffset; }
+  uint64_t getReturnSaveOffset() const { return ReturnSaveOffset; }
 
   /// getTOCSaveOffset - Return the previous frame offset to save the
   /// TOC register -- 64-bit SVR4 ABI only.
-  unsigned getTOCSaveOffset() const;
+  uint64_t getTOCSaveOffset() const;
 
   /// getFramePointerSaveOffset - Return the previous frame offset to save the
   /// frame pointer.
-  unsigned getFramePointerSaveOffset() const;
+  uint64_t getFramePointerSaveOffset() const;
 
   /// getBasePointerSaveOffset - Return the previous frame offset to save the
   /// base pointer.
-  unsigned getBasePointerSaveOffset() const;
+  uint64_t getBasePointerSaveOffset() const;
 
   /// getLinkageSize - Return the size of the PowerPC ABI linkage area.
   ///
diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -279,11 +279,11 @@
 
 /// determineFrameLayoutAndUpdate - Determine the size of the frame and maximum
 /// call frame size. Update the MachineFunction object with the stack size.
-unsigned
+uint64_t
 PPCFrameLowering::determineFrameLayoutAndUpdate(MachineFunction &MF,
                                                 bool UseEstimate) const {
   unsigned NewMaxCallFrameSize = 0;
-  unsigned FrameSize = determineFrameLayout(MF, UseEstimate,
+  uint64_t FrameSize = determineFrameLayout(MF, UseEstimate,
                                             &NewMaxCallFrameSize);
   MF.getFrameInfo().setStackSize(FrameSize);
   MF.getFrameInfo().setMaxCallFrameSize(NewMaxCallFrameSize);
@@ -292,7 +292,7 @@
 
 /// determineFrameLayout - Determine the size of the frame and maximum call
 /// frame size.
-unsigned
+uint64_t
 PPCFrameLowering::determineFrameLayout(const MachineFunction &MF,
                                        bool UseEstimate,
                                        unsigned *NewMaxCallFrameSize) const {
@@ -300,7 +300,7 @@
   const PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
 
   // Get the number of bytes to allocate from the FrameInfo
-  unsigned FrameSize =
+  uint64_t FrameSize =
     UseEstimate ? MFI.estimateStackSize(MF) : MFI.getStackSize();
 
   // Get stack alignments. The frame must be aligned to the greatest of these:
@@ -624,9 +624,9 @@
   assert((isSVR4ABI || Subtarget.isAIXABI()) && "Unsupported PPC ABI.");
 
   // Work out frame sizes.
-  unsigned FrameSize = determineFrameLayoutAndUpdate(MF);
-  int NegFrameSize = -FrameSize;
-  if (!isInt<32>(NegFrameSize))
+  uint64_t FrameSize = determineFrameLayoutAndUpdate(MF);
+  int64_t NegFrameSize = -FrameSize;
+  if (!isInt<32>(FrameSize) || !isInt<32>(NegFrameSize))
     llvm_unreachable("Unhandled stack size!");
 
   if (MFI.isFrameAddressTaken())
@@ -692,9 +692,9 @@
 
   SingleScratchReg = ScratchReg == TempReg;
 
-  int LROffset = getReturnSaveOffset();
+  int64_t LROffset = getReturnSaveOffset();
 
-  int FPOffset = 0;
+  int64_t FPOffset = 0;
   if (HasFP) {
     MachineFrameInfo &MFI = MF.getFrameInfo();
     int FPIndex = FI->getFramePointerSaveIndex();
@@ -702,7 +702,7 @@
     FPOffset = MFI.getObjectOffset(FPIndex);
   }
 
-  int BPOffset = 0;
+  int64_t BPOffset = 0;
   if (HasBP) {
     MachineFrameInfo &MFI = MF.getFrameInfo();
     int BPIndex = FI->getBasePointerSaveIndex();
@@ -710,7 +710,7 @@
     BPOffset = MFI.getObjectOffset(BPIndex);
   }
 
-  int PBPOffset = 0;
+  int64_t PBPOffset = 0;
   if (FI->usesPICBase()) {
     MachineFrameInfo &MFI = MF.getFrameInfo();
     int PBPIndex = FI->getPICBasePointerSaveIndex();
@@ -854,7 +854,7 @@
     // ABI.
     if (HasROPProtect) {
       const int SaveIndex = FI->getROPProtectionHashSaveIndex();
-      const int ImmOffset = MFI.getObjectOffset(SaveIndex);
+      const int64_t ImmOffset = MFI.getObjectOffset(SaveIndex);
       assert((ImmOffset <= -8 && ImmOffset >= -512) &&
              "ROP hash save offset out of range.");
       assert(((ImmOffset & 0x7) == 0) &&
@@ -1212,7 +1212,7 @@
         BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
           .addCFIIndex(CFIRegister);
       } else {
-        int Offset = MFI.getObjectOffset(CSI[I].getFrameIdx());
+        int64_t Offset = MFI.getObjectOffset(CSI[I].getFrameIdx());
         // We have changed the object offset above but we do not want to change
         // the actual offsets in the CFI instruction so we have to undo the
         // offset change here.
@@ -1550,7 +1550,7 @@
   const MachineFrameInfo &MFI = MF.getFrameInfo();
 
   // Get the number of bytes allocated from the FrameInfo.
-  int FrameSize = MFI.getStackSize();
+  int64_t FrameSize = MFI.getStackSize();
 
   // Get processor type.
   bool isPPC64 = Subtarget.isPPC64();
@@ -1592,9 +1592,9 @@
                                                      : PPC::MTOCRF);
   const MCInstrDesc &HashChk =
       TII.get(HasPrivileged ? PPC::HASHCHKP : PPC::HASHCHK);
-  int LROffset = getReturnSaveOffset();
+  int64_t LROffset = getReturnSaveOffset();
 
-  int FPOffset = 0;
+  int64_t FPOffset = 0;
 
   // Using the same bool variable as below to suppress compiler warnings.
   bool SingleScratchReg = findScratchRegister(&MBB, true, false, &ScratchReg,
@@ -1610,14 +1610,14 @@
     FPOffset = MFI.getObjectOffset(FPIndex);
   }
 
-  int BPOffset = 0;
+  int64_t BPOffset = 0;
   if (HasBP) {
       int BPIndex = FI->getBasePointerSaveIndex();
       assert(BPIndex && "No Base Pointer Save Slot!");
       BPOffset = MFI.getObjectOffset(BPIndex);
   }
 
-  int PBPOffset = 0;
+  int64_t PBPOffset = 0;
   if (FI->usesPICBase()) {
     int PBPIndex = FI->getPICBasePointerSaveIndex();
     assert(PBPIndex && "No PIC Base Pointer Save Slot!");
@@ -1865,7 +1865,7 @@
     // hash and then compare it to the hash stored in the prologue.
     if (HasROPProtect) {
       const int SaveIndex = FI->getROPProtectionHashSaveIndex();
-      const int ImmOffset = MFI.getObjectOffset(SaveIndex);
+      const int64_t ImmOffset = MFI.getObjectOffset(SaveIndex);
       assert((ImmOffset <= -8 && ImmOffset >= -512) &&
              "ROP hash check location offset out of range.");
       assert(((ImmOffset & 0x7) == 0) &&
@@ -2680,15 +2680,15 @@
   return true;
 }
 
-unsigned PPCFrameLowering::getTOCSaveOffset() const {
+uint64_t PPCFrameLowering::getTOCSaveOffset() const {
   return TOCSaveOffset;
 }
 
-unsigned PPCFrameLowering::getFramePointerSaveOffset() const {
+uint64_t PPCFrameLowering::getFramePointerSaveOffset() const {
   return FramePointerSaveOffset;
 }
 
-unsigned PPCFrameLowering::getBasePointerSaveOffset() const {
+uint64_t PPCFrameLowering::getBasePointerSaveOffset() const {
   return BasePointerSaveOffset;
 }
 
diff --git a/llvm/test/CodeGen/PowerPC/huge-frame-size.ll b/llvm/test/CodeGen/PowerPC/huge-frame-size.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/huge-frame-size.ll
@@ -0,0 +1,17 @@
+; REQUIRES: asserts
+; RUN: not --crash llc -verify-machineinstrs -mtriple=powerpc64le-linux-gnu < %s \
+; RUN:   2>&1 | FileCheck --check-prefix=CHECK-LE %s
+; RUN: not --crash llc -verify-machineinstrs -mtriple=powerpc64-ibm-aix-xcoff < %s \
+; RUN:   2>&1 | FileCheck --check-prefix=CHECK-BE %s
+
+declare void @bar(i8*)
+
+define void @foo(i8 %x) {
+; CHECK-LE: Unhandled stack size
+; CHECK-BE: Unhandled stack size
+entry:
+  %a = alloca i8, i64 4294967296, align 16
+  %b = getelementptr i8, i8* %a, i64 0
+  store volatile i8 %x, i8* %b
+  ret void
+}