diff --git a/llvm/include/llvm/Analysis/TargetTransformInfo.h b/llvm/include/llvm/Analysis/TargetTransformInfo.h
--- a/llvm/include/llvm/Analysis/TargetTransformInfo.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfo.h
@@ -98,7 +98,7 @@
   Loop *L = nullptr;
   BasicBlock *ExitBlock = nullptr;
   BranchInst *ExitBranch = nullptr;
-  const SCEV *ExitCount = nullptr;
+  const SCEV *TripCount = nullptr;
   IntegerType *CountType = nullptr;
   Value *LoopDecrement = nullptr; // Decrement the loop counter by this
                                   // value in every iteration.
@@ -111,7 +111,8 @@
                                   // produces an i1 to guard the loop entry.
   bool isHardwareLoopCandidate(ScalarEvolution &SE, LoopInfo &LI,
                                DominatorTree &DT, bool ForceNestedLoop = false,
-                               bool ForceHardwareLoopPHI = false);
+                               bool ForceHardwareLoopPHI = false,
+                               bool ForceGuardLoopEntry = false);
   bool canAnalyze(LoopInfo &LI);
 };
 
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -100,10 +100,12 @@
 bool HardwareLoopInfo::isHardwareLoopCandidate(ScalarEvolution &SE,
                                                LoopInfo &LI, DominatorTree &DT,
                                                bool ForceNestedLoop,
-                                               bool ForceHardwareLoopPHI) {
+                                               bool ForceHardwareLoopPHI,
+                                               bool ForceGuardLoopEntry) {
   SmallVector<BasicBlock *, 4> ExitingBlocks;
   L->getExitingBlocks(ExitingBlocks);
 
+  const SCEV *ExitCount = nullptr;
   for (BasicBlock *BB : ExitingBlocks) {
     // If we pass the updated counter back through a phi, we need to know
     // which latch the updated value will be coming from.
@@ -173,6 +175,35 @@
 
   if (!ExitBlock)
     return false;
+
+  assert(ExitCount->getType()->isIntegerTy() &&
+         "Count type must be integer!\n");
+
+  assert((SE.getTypeSizeInBits(ExitCount->getType()) <=
+          CountType->getBitWidth()) &&
+         "Invalid loop count type!\n");
+
+  // If we can prove that ExitCount + 1 doesn't overflow(can't be zero),
+  // 1: we can use test and set form loop count.
+  // 2: if we need a zero extend, we can first do +1 before extend
+  //    for some const folding.
+  if (SE.isLoopEntryGuardedByCond(
+          L, ICmpInst::ICMP_NE,
+          SE.getAddExpr(ExitCount, SE.getOne(ExitCount->getType())),
+          SE.getZero(ExitCount->getType()))) {
+    if (ExitCount->getType() != CountType)
+      TripCount = SE.getZeroExtendExpr(
+          SE.getAddExpr(ExitCount, SE.getOne(ExitCount->getType())), CountType);
+    else
+      TripCount = SE.getAddExpr(SE.getNoopOrZeroExtend(ExitCount, CountType),
+                                SE.getOne(CountType));
+    PerformEntryTest |= ForceGuardLoopEntry;
+  } else {
+    TripCount = SE.getAddExpr(SE.getNoopOrZeroExtend(ExitCount, CountType),
+                              SE.getOne(CountType));
+    PerformEntryTest = false;
+  }
+
   return true;
 }
 
diff --git a/llvm/lib/CodeGen/HardwareLoops.cpp b/llvm/lib/CodeGen/HardwareLoops.cpp
--- a/llvm/lib/CodeGen/HardwareLoops.cpp
+++ b/llvm/lib/CodeGen/HardwareLoops.cpp
@@ -184,15 +184,12 @@
 
   public:
     HardwareLoop(HardwareLoopInfo &Info, ScalarEvolution &SE,
-                 const DataLayout &DL,
-                 OptimizationRemarkEmitter *ORE) :
-      SE(SE), DL(DL), ORE(ORE), L(Info.L), M(L->getHeader()->getModule()),
-      ExitCount(Info.ExitCount),
-      CountType(Info.CountType),
-      ExitBranch(Info.ExitBranch),
-      LoopDecrement(Info.LoopDecrement),
-      UsePHICounter(Info.CounterInReg),
-      UseLoopGuard(Info.PerformEntryTest) { }
+                 const DataLayout &DL, OptimizationRemarkEmitter *ORE)
+        : SE(SE), DL(DL), ORE(ORE), L(Info.L), M(L->getHeader()->getModule()),
+          TripCount(Info.TripCount), CountType(Info.CountType),
+          ExitBranch(Info.ExitBranch), LoopDecrement(Info.LoopDecrement),
+          UsePHICounter(Info.CounterInReg),
+          UseLoopGuard(Info.PerformEntryTest) {}
 
     void Create();
 
@@ -200,15 +197,15 @@
     ScalarEvolution &SE;
     const DataLayout &DL;
     OptimizationRemarkEmitter *ORE = nullptr;
-    Loop *L                 = nullptr;
-    Module *M               = nullptr;
-    const SCEV *ExitCount   = nullptr;
-    Type *CountType         = nullptr;
-    BranchInst *ExitBranch  = nullptr;
-    Value *LoopDecrement    = nullptr;
-    bool UsePHICounter      = false;
-    bool UseLoopGuard       = false;
-    BasicBlock *BeginBB     = nullptr;
+    Loop *L = nullptr;
+    Module *M = nullptr;
+    const SCEV *TripCount = nullptr;
+    Type *CountType = nullptr;
+    BranchInst *ExitBranch = nullptr;
+    Value *LoopDecrement = nullptr;
+    bool UsePHICounter = false;
+    bool UseLoopGuard = false;
+    BasicBlock *BeginBB = nullptr;
   };
 }
 
@@ -287,7 +284,8 @@
   LLVM_DEBUG(dbgs() << "HWLoops: Try to convert profitable loop: " << *L);
 
   if (!HWLoopInfo.isHardwareLoopCandidate(*SE, *LI, *DT, ForceNestedLoop,
-                                          ForceHardwareLoopPHI)) {
+                                          ForceHardwareLoopPHI,
+                                          ForceGuardLoopEntry)) {
     // TODO: there can be many reasons a loop is not considered a
     // candidate, so we should let isHardwareLoopCandidate fill in the
     // reason and then report a better message here.
@@ -296,7 +294,7 @@
   }
 
   assert(
-      (HWLoopInfo.ExitBlock && HWLoopInfo.ExitBranch && HWLoopInfo.ExitCount) &&
+      (HWLoopInfo.ExitBlock && HWLoopInfo.ExitBranch && HWLoopInfo.TripCount) &&
       "Hardware Loop must have set exit info.");
 
   BasicBlock *Preheader = L->getLoopPreheader();
@@ -381,43 +379,29 @@
   // loop counter and tests that is not zero?
 
   SCEVExpander SCEVE(SE, DL, "loopcnt");
-  if (!ExitCount->getType()->isPointerTy() &&
-      ExitCount->getType() != CountType)
-    ExitCount = SE.getZeroExtendExpr(ExitCount, CountType);
-
-  ExitCount = SE.getAddExpr(ExitCount, SE.getOne(CountType));
-
-  // If we're trying to use the 'test and set' form of the intrinsic, we need
-  // to replace a conditional branch that is controlling entry to the loop. It
-  // is likely (guaranteed?) that the preheader has an unconditional branch to
-  // the loop header, so also check if it has a single predecessor.
-  if (SE.isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, ExitCount,
-                                  SE.getZero(ExitCount->getType()))) {
-    LLVM_DEBUG(dbgs() << " - Attempting to use test.set counter.\n");
-    UseLoopGuard |= ForceGuardLoopEntry;
-  } else
-    UseLoopGuard = false;
 
+  // If we're trying to use the 'test and set' form of the intrinsic, it is
+  // likely (guaranteed?) that the preheader has an unconditional branch to the
+  // loop header, so also check if it has a single predecessor.
   BasicBlock *BB = L->getLoopPreheader();
   if (UseLoopGuard && BB->getSinglePredecessor() &&
       cast<BranchInst>(BB->getTerminator())->isUnconditional()) {
     BasicBlock *Predecessor = BB->getSinglePredecessor();
     // If it's not safe to create a while loop then don't force it and create a
     // do-while loop instead
-    if (!isSafeToExpandAt(ExitCount, Predecessor->getTerminator(), SE))
-        UseLoopGuard = false;
+    if (!isSafeToExpandAt(TripCount, Predecessor->getTerminator(), SE))
+      UseLoopGuard = false;
     else
-        BB = Predecessor;
+      BB = Predecessor;
   }
 
-  if (!isSafeToExpandAt(ExitCount, BB->getTerminator(), SE)) {
-    LLVM_DEBUG(dbgs() << "- Bailing, unsafe to expand ExitCount "
-               << *ExitCount << "\n");
+  if (!isSafeToExpandAt(TripCount, BB->getTerminator(), SE)) {
+    LLVM_DEBUG(dbgs() << "- Bailing, unsafe to expand TripCount " << *TripCount
+                      << "\n");
     return nullptr;
   }
 
-  Value *Count = SCEVE.expandCodeFor(ExitCount, CountType,
-                                     BB->getTerminator());
+  Value *Count = SCEVE.expandCodeFor(TripCount, CountType, BB->getTerminator());
 
   // FIXME: We've expanded Count where we hope to insert the counter setting
   // intrinsic. But, in the case of the 'test and set' form, we may fallback to
diff --git a/llvm/test/CodeGen/PowerPC/loop-instr-prep-non-const-increasement.ll b/llvm/test/CodeGen/PowerPC/loop-instr-prep-non-const-increasement.ll
--- a/llvm/test/CodeGen/PowerPC/loop-instr-prep-non-const-increasement.ll
+++ b/llvm/test/CodeGen/PowerPC/loop-instr-prep-non-const-increasement.ll
@@ -20,10 +20,8 @@
 ; CHECK-NEXT:    blt cr0, .LBB0_4
 ; CHECK-NEXT:  # %bb.1: # %for.body.preheader
 ; CHECK-NEXT:    addi r6, r3, 5
-; CHECK-NEXT:    addi r3, r4, -1
+; CHECK-NEXT:    clrldi r3, r4, 32
 ; CHECK-NEXT:    extsw r5, r5
-; CHECK-NEXT:    clrldi r3, r3, 32
-; CHECK-NEXT:    addi r3, r3, 1
 ; CHECK-NEXT:    mtctr r3
 ; CHECK-NEXT:    li r3, 0
 ; CHECK-NEXT:    .p2align 5
@@ -87,23 +85,21 @@
 ; CHECK-NEXT:    cmpwi r4, 1
 ; CHECK-NEXT:    blt cr0, .LBB1_4
 ; CHECK-NEXT:  # %bb.1: # %for.body.preheader
-; CHECK-NEXT:    addi r4, r4, -1
-; CHECK-NEXT:    addi r3, r3, 1000
+; CHECK-NEXT:    addi r6, r3, 1000
+; CHECK-NEXT:    clrldi r3, r4, 32
 ; CHECK-NEXT:    extsw r5, r5
-; CHECK-NEXT:    li r6, 0
-; CHECK-NEXT:    clrldi r4, r4, 32
-; CHECK-NEXT:    addi r4, r4, 1
-; CHECK-NEXT:    mtctr r4
 ; CHECK-NEXT:    li r4, 0
+; CHECK-NEXT:    mtctr r3
+; CHECK-NEXT:    li r3, 0
 ; CHECK-NEXT:    .p2align 4
 ; CHECK-NEXT:  .LBB1_2: # %for.body
 ; CHECK-NEXT:    #
-; CHECK-NEXT:    lbzx r7, r3, r6
-; CHECK-NEXT:    add r6, r6, r5
-; CHECK-NEXT:    add r4, r7, r4
+; CHECK-NEXT:    lbzx r7, r6, r4
+; CHECK-NEXT:    add r4, r4, r5
+; CHECK-NEXT:    add r3, r7, r3
 ; CHECK-NEXT:    bdnz .LBB1_2
 ; CHECK-NEXT:  # %bb.3: # %for.cond.cleanup
-; CHECK-NEXT:    clrldi r3, r4, 56
+; CHECK-NEXT:    clrldi r3, r3, 56
 ; CHECK-NEXT:    blr
 ; CHECK-NEXT:  .LBB1_4:
 ; CHECK-NEXT:    li r3, 0
diff --git a/llvm/test/CodeGen/PowerPC/mma-phi-accs.ll b/llvm/test/CodeGen/PowerPC/mma-phi-accs.ll
--- a/llvm/test/CodeGen/PowerPC/mma-phi-accs.ll
+++ b/llvm/test/CodeGen/PowerPC/mma-phi-accs.ll
@@ -263,9 +263,7 @@
 ; CHECK-NEXT:    cmpwi r4, 1
 ; CHECK-NEXT:    blt cr0, .LBB3_5
 ; CHECK-NEXT:  .LBB3_3: # %for.body.preheader
-; CHECK-NEXT:    addi r3, r4, -1
-; CHECK-NEXT:    clrldi r3, r3, 32
-; CHECK-NEXT:    addi r3, r3, 1
+; CHECK-NEXT:    clrldi r3, r4, 32
 ; CHECK-NEXT:    mtctr r3
 ; CHECK-NEXT:    .p2align 4
 ; CHECK-NEXT:  .LBB3_4: # %for.body
@@ -295,9 +293,7 @@
 ; CHECK-BE-NEXT:    cmpwi r4, 1
 ; CHECK-BE-NEXT:    blt cr0, .LBB3_5
 ; CHECK-BE-NEXT:  .LBB3_3: # %for.body.preheader
-; CHECK-BE-NEXT:    addi r3, r4, -1
-; CHECK-BE-NEXT:    clrldi r3, r3, 32
-; CHECK-BE-NEXT:    addi r3, r3, 1
+; CHECK-BE-NEXT:    clrldi r3, r4, 32
 ; CHECK-BE-NEXT:    mtctr r3
 ; CHECK-BE-NEXT:    .p2align 4
 ; CHECK-BE-NEXT:  .LBB3_4: # %for.body