diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp
index 4a64867..b8cbf5d 100644
--- a/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/lib/Target/ARM/ARMFrameLowering.cpp
@@ -297,7 +297,7 @@
 
 void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   assert(MBBI->getDesc().isReturn() &&
          "Can only insert epilog into returning blocks");
   unsigned RetOpcode = MBBI->getOpcode();
@@ -378,7 +378,7 @@
   if (RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNdiND ||
       RetOpcode == ARM::TCRETURNri || RetOpcode == ARM::TCRETURNriND) {
     // Tail call return: adjust the stack pointer and jump to callee.
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
 
     // Jump to label or value in register.
diff --git a/lib/Target/ARM/Thumb1FrameLowering.cpp b/lib/Target/ARM/Thumb1FrameLowering.cpp
index 8a6dda8..233e165 100644
--- a/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -189,7 +189,7 @@
 
 void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF,
                                    MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   assert((MBBI->getOpcode() == ARM::tBX_RET ||
           MBBI->getOpcode() == ARM::tPOP_RET) &&
          "Can only insert epilog into returning blocks");
diff --git a/lib/Target/Alpha/AlphaFrameLowering.cpp b/lib/Target/Alpha/AlphaFrameLowering.cpp
index 949bd4f..690cd1d 100644
--- a/lib/Target/Alpha/AlphaFrameLowering.cpp
+++ b/lib/Target/Alpha/AlphaFrameLowering.cpp
@@ -104,7 +104,7 @@
 void AlphaFrameLowering::emitEpilogue(MachineFunction &MF,
                                   MachineBasicBlock &MBB) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
 
   assert((MBBI->getOpcode() == Alpha::RETDAG ||
diff --git a/lib/Target/Blackfin/BlackfinFrameLowering.cpp b/lib/Target/Blackfin/BlackfinFrameLowering.cpp
index 594325f..08bb952 100644
--- a/lib/Target/Blackfin/BlackfinFrameLowering.cpp
+++ b/lib/Target/Blackfin/BlackfinFrameLowering.cpp
@@ -90,7 +90,7 @@
     static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
   const BlackfinInstrInfo &TII =
     *static_cast<const BlackfinInstrInfo*>(MF.getTarget().getInstrInfo());
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   DebugLoc dl = MBBI->getDebugLoc();
 
   int FrameSize = MFI->getStackSize();
diff --git a/lib/Target/CellSPU/SPUFrameLowering.cpp b/lib/Target/CellSPU/SPUFrameLowering.cpp
index 596d39c..432f4a1 100644
--- a/lib/Target/CellSPU/SPUFrameLowering.cpp
+++ b/lib/Target/CellSPU/SPUFrameLowering.cpp
@@ -187,7 +187,7 @@
     // sufficient number instructions in the basic block. Note that
     // this is just a best guess based on the basic block's size.
     if (MBB.size() >= (unsigned) SPUFrameLowering::branchHintPenalty()) {
-      MachineBasicBlock::iterator MBBI = prior(MBB.end());
+      MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
       dl = MBBI->getDebugLoc();
 
       // Insert terminator label
@@ -199,7 +199,7 @@
 
 void SPUFrameLowering::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   const SPUInstrInfo &TII =
     *static_cast<const SPUInstrInfo*>(MF.getTarget().getInstrInfo());
   const MachineFrameInfo *MFI = MF.getFrameInfo();
diff --git a/lib/Target/MBlaze/MBlazeFrameLowering.cpp b/lib/Target/MBlaze/MBlazeFrameLowering.cpp
index e501621..e763902 100644
--- a/lib/Target/MBlaze/MBlazeFrameLowering.cpp
+++ b/lib/Target/MBlaze/MBlazeFrameLowering.cpp
@@ -386,7 +386,7 @@
 
 void MBlazeFrameLowering::emitEpilogue(MachineFunction &MF,
                                    MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   MachineFrameInfo *MFI            = MF.getFrameInfo();
   MBlazeFunctionInfo *MBlazeFI     = MF.getInfo<MBlazeFunctionInfo>();
   const MBlazeInstrInfo &TII =
diff --git a/lib/Target/MSP430/MSP430FrameLowering.cpp b/lib/Target/MSP430/MSP430FrameLowering.cpp
index 9d37353..c99f4ab 100644
--- a/lib/Target/MSP430/MSP430FrameLowering.cpp
+++ b/lib/Target/MSP430/MSP430FrameLowering.cpp
@@ -110,7 +110,7 @@
   const MSP430InstrInfo &TII =
     *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
 
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   unsigned RetOpcode = MBBI->getOpcode();
   DebugLoc DL = MBBI->getDebugLoc();
 
diff --git a/lib/Target/Mips/MipsFrameLowering.cpp b/lib/Target/Mips/MipsFrameLowering.cpp
index a81f947..711887a 100644
--- a/lib/Target/Mips/MipsFrameLowering.cpp
+++ b/lib/Target/Mips/MipsFrameLowering.cpp
@@ -266,7 +266,7 @@
 
 void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
                                  MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   MachineFrameInfo *MFI            = MF.getFrameInfo();
   MipsFunctionInfo *MipsFI         = MF.getInfo<MipsFunctionInfo>();
   const MipsInstrInfo &TII =
diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index 4c5b94d..6aca6b0 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -497,7 +497,8 @@
 
 void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
+  assert(MBBI != MBB.end() && "Returning block has no terminator");
   const PPCInstrInfo &TII =
     *static_cast<const PPCInstrInfo*>(MF.getTarget().getInstrInfo());
 
@@ -676,29 +677,29 @@
           .addReg(TmpReg);
      }
   } else if (RetOpcode == PPC::TCRETURNdi) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILB)).
       addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
   } else if (RetOpcode == PPC::TCRETURNri) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     assert(MBBI->getOperand(0).isReg() && "Expecting register operand.");
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBCTR));
   } else if (RetOpcode == PPC::TCRETURNai) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBA)).addImm(JumpTarget.getImm());
   } else if (RetOpcode == PPC::TCRETURNdi8) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILB8)).
       addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
   } else if (RetOpcode == PPC::TCRETURNri8) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     assert(MBBI->getOperand(0).isReg() && "Expecting register operand.");
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBCTR8));
   } else if (RetOpcode == PPC::TCRETURNai8) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
     BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBA8)).addImm(JumpTarget.getImm());
   }
diff --git a/lib/Target/Sparc/SparcFrameLowering.cpp b/lib/Target/Sparc/SparcFrameLowering.cpp
index 1efd707..320c8ca 100644
--- a/lib/Target/Sparc/SparcFrameLowering.cpp
+++ b/lib/Target/Sparc/SparcFrameLowering.cpp
@@ -69,7 +69,7 @@
 
 void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
                                   MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   const SparcInstrInfo &TII =
     *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
   DebugLoc dl = MBBI->getDebugLoc();
diff --git a/lib/Target/SystemZ/SystemZFrameLowering.cpp b/lib/Target/SystemZ/SystemZFrameLowering.cpp
index 05c2b89..2ad84a2 100644
--- a/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -141,7 +141,7 @@
 void SystemZFrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   const SystemZInstrInfo &TII =
     *static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
   SystemZMachineFunctionInfo *SystemZMFI =
diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index 7c7b4f3..02010f8 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -646,7 +646,8 @@
   X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
   const X86RegisterInfo *RegInfo = TM.getRegisterInfo();
   const X86InstrInfo &TII = *TM.getInstrInfo();
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
+  assert(MBBI != MBB.end() && "Returning block has no instructions");
   unsigned RetOpcode = MBBI->getOpcode();
   DebugLoc DL = MBBI->getDebugLoc();
   bool Is64Bit = STI.is64Bit();
@@ -709,7 +710,7 @@
     MachineBasicBlock::iterator PI = prior(MBBI);
     unsigned Opc = PI->getOpcode();
 
-    if (Opc != X86::POP32r && Opc != X86::POP64r &&
+    if (Opc != X86::POP32r && Opc != X86::POP64r && Opc != X86::DBG_VALUE &&
         !PI->getDesc().isTerminator())
       break;
 
@@ -756,7 +757,7 @@
 
   // We're returning from function via eh_return.
   if (RetOpcode == X86::EH_RETURN || RetOpcode == X86::EH_RETURN64) {
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
     MachineOperand &DestAddr  = MBBI->getOperand(0);
     assert(DestAddr.isReg() && "Offset should be in register!");
     BuildMI(MBB, MBBI, DL,
@@ -768,7 +769,7 @@
              RetOpcode == X86::TCRETURNmi64) {
     bool isMem = RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64;
     // Tail call return: adjust the stack pointer and jump to callee.
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getFirstTerminator();
     MachineOperand &JumpTarget = MBBI->getOperand(0);
     MachineOperand &StackAdjust = MBBI->getOperand(isMem ? 5 : 1);
     assert(StackAdjust.isImm() && "Expecting immediate value.");
@@ -826,7 +827,7 @@
              (X86FI->getTCReturnAddrDelta() < 0)) {
     // Add the return addr area delta back since we are not tail calling.
     int delta = -1*X86FI->getTCReturnAddrDelta();
-    MBBI = prior(MBB.end());
+    MBBI = MBB.getLastNonDebugInstr();
 
     // Check for possible merge with preceeding ADD instruction.
     delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);