Index: include/llvm/CodeGen/MachineBasicBlock.h
===================================================================
--- include/llvm/CodeGen/MachineBasicBlock.h
+++ include/llvm/CodeGen/MachineBasicBlock.h
@@ -814,10 +814,10 @@
 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
 /// const_instr_iterator} and the respective reverse iterators.
 template<typename IterT>
-inline IterT skipDebugInstructionsForward(IterT It, IterT End) {
+inline bool skipDebugInstructionsForward(IterT &It, IterT End) {
   while (It != End && It->isDebugValue())
     It++;
-  return It;
+  return It == End;
 }
 
 /// Decrement \p It until it points to a non-debug instruction or to \p Begin
@@ -825,10 +825,10 @@
 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
 /// const_instr_iterator} and the respective reverse iterators.
 template<class IterT>
-inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin) {
+inline bool skipDebugInstructionsBackward(IterT &It, IterT Begin) {
   while (It != Begin && It->isDebugValue())
     It--;
-  return It;
+  return It == Begin;
 }
 
 } // End llvm namespace
Index: lib/CodeGen/BranchFolding.cpp
===================================================================
--- lib/CodeGen/BranchFolding.cpp
+++ lib/CodeGen/BranchFolding.cpp
@@ -1713,8 +1713,8 @@
 
   // The terminator is probably a conditional branch, try not to separate the
   // branch from condition setting instruction.
-  MachineBasicBlock::iterator PI =
-    skipDebugInstructionsBackward(std::prev(Loc), MBB->begin());
+  MachineBasicBlock::iterator PI = std::prev(Loc);
+  skipDebugInstructionsBackward(PI, MBB->begin());
 
   bool IsDef = false;
   for (const MachineOperand &MO : PI->operands()) {
@@ -1808,8 +1808,8 @@
   MachineBasicBlock::iterator FIE = FBB->end();
   while (TIB != TIE && FIB != FIE) {
     // Skip dbg_value instructions. These do not count.
-    TIB = skipDebugInstructionsForward(TIB, TIE);
-    FIB = skipDebugInstructionsForward(FIB, FIE);
+    skipDebugInstructionsForward(TIB, TIE);
+    skipDebugInstructionsForward(FIB, FIE);
     if (TIB == TIE || FIB == FIE)
       break;
 
Index: lib/CodeGen/IfConversion.cpp
===================================================================
--- lib/CodeGen/IfConversion.cpp
+++ lib/CodeGen/IfConversion.cpp
@@ -619,11 +619,9 @@
 
   while (TIB != TIE && FIB != FIE) {
     // Skip dbg_value instructions. These do not count.
-    TIB = skipDebugInstructionsForward(TIB, TIE);
-    if (TIB == TIE)
+    if(skipDebugInstructionsForward(TIB, TIE))
       break;
-    FIB = skipDebugInstructionsForward(FIB, FIE);
-    if (FIB == FIE)
+    if(skipDebugInstructionsForward(FIB, FIE))
       break;
     if (!TIB->isIdenticalTo(*FIB))
       break;
@@ -663,11 +661,9 @@
   while (RTIE != RTIB && RFIE != RFIB) {
     // Skip dbg_value instructions. These do not count.
     // Note that these are reverse iterators going forward.
-    RTIE = skipDebugInstructionsForward(RTIE, RTIB);
-    if (RTIE == RTIB)
+    if (skipDebugInstructionsForward(RTIE, RTIB))
       break;
-    RFIE = skipDebugInstructionsForward(RFIE, RFIB);
-    if (RFIE == RFIB)
+    if (skipDebugInstructionsForward(RFIE, RFIB))
       break;
     if (!RTIE->isIdenticalTo(*RFIE))
       break;
Index: lib/CodeGen/MachineBasicBlock.cpp
===================================================================
--- lib/CodeGen/MachineBasicBlock.cpp
+++ lib/CodeGen/MachineBasicBlock.cpp
@@ -191,7 +191,9 @@
 
 MachineBasicBlock::iterator MachineBasicBlock::getFirstNonDebugInstr() {
   // Skip over begin-of-block dbg_value instructions.
-  return skipDebugInstructionsForward(begin(), end());
+  iterator I = begin();
+  skipDebugInstructionsForward(I, end());
+  return I;
 }
 
 MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
@@ -1138,10 +1140,9 @@
 DebugLoc
 MachineBasicBlock::findDebugLoc(instr_iterator MBBI) {
   // Skip debug declarations, we don't want a DebugLoc from them.
-  MBBI = skipDebugInstructionsForward(MBBI, instr_end());
-  if (MBBI != instr_end())
-    return MBBI->getDebugLoc();
-  return {};
+  if (skipDebugInstructionsForward(MBBI, instr_end()))
+    return {};
+  return MBBI->getDebugLoc();
 }
 
 /// Return probability of the edge from this block to MBB.
Index: lib/CodeGen/MachineCSE.cpp
===================================================================
--- lib/CodeGen/MachineCSE.cpp
+++ lib/CodeGen/MachineCSE.cpp
@@ -177,7 +177,7 @@
   unsigned LookAheadLeft = LookAheadLimit;
   while (LookAheadLeft) {
     // Skip over dbg_value's.
-    I = skipDebugInstructionsForward(I, E);
+    skipDebugInstructionsForward(I, E);
 
     if (I == E)
       // Reached end of block, register is obviously dead.
Index: lib/CodeGen/RegisterPressure.cpp
===================================================================
--- lib/CodeGen/RegisterPressure.cpp
+++ lib/CodeGen/RegisterPressure.cpp
@@ -266,9 +266,8 @@
 
 
 SlotIndex RegPressureTracker::getCurrSlot() const {
-  MachineBasicBlock::const_iterator IdxPos =
-    skipDebugInstructionsForward(CurrPos, MBB->end());
-  if (IdxPos == MBB->end())
+  auto IdxPos = CurrPos;
+  if(skipDebugInstructionsForward(IdxPos, MBB->end()))
     return LIS->getMBBEndIdx(MBB);
   return LIS->getInstructionIndex(*IdxPos).getRegSlot();
 }
@@ -816,7 +815,7 @@
     static_cast<RegionPressure&>(P).openTop(CurrPos);
 
   // Find the previous instruction.
-  CurrPos = skipDebugInstructionsBackward(std::prev(CurrPos), MBB->begin());
+  skipDebugInstructionsBackward(--CurrPos, MBB->begin());
 
   SlotIndex SlotIdx;
   if (RequireIntervals)
@@ -892,7 +891,7 @@
   bumpDeadDefs(RegOpers.DeadDefs);
 
   // Find the next instruction.
-  CurrPos = skipDebugInstructionsForward(std::next(CurrPos), MBB->end());
+  skipDebugInstructionsForward(++CurrPos, MBB->end());
 }
 
 void RegPressureTracker::advance() {