Index: lib/Transforms/Scalar/IndVarSimplify.cpp
===================================================================
--- lib/Transforms/Scalar/IndVarSimplify.cpp
+++ lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -85,6 +85,24 @@
 namespace {
 struct RewritePhi;
 
+struct OriginalIVInfo {
+  bool HasNUW;
+  bool HasNSW;
+  bool IsSigned;
+  Type *OriginalType;
+
+  OriginalIVInfo(bool HasNUW, bool HasNSW,
+                 bool IsSigned, Type *OriginalType) :
+                 HasNUW(HasNUW), HasNSW(HasNSW),
+                 IsSigned(IsSigned),
+                 OriginalType(OriginalType){};
+
+  OriginalIVInfo() {};
+
+};
+
+typedef ValueMap<Value *, std::unique_ptr<OriginalIVInfo>> WidenedIVMapType;
+
 class IndVarSimplify {
   LoopInfo *LI;
   ScalarEvolution *SE;
@@ -93,6 +111,8 @@
   TargetLibraryInfo *TLI;
   const TargetTransformInfo *TTI;
 
+  WidenedIVMapType WidenedIVMap;
+
   SmallVector<WeakVH, 16> DeadInsts;
   bool Changed = false;
 
@@ -907,7 +927,7 @@
     assert(L->getHeader() == OrigPhi->getParent() && "Phi must be an IV");
   }
 
-  PHINode *createWideIV(SCEVExpander &Rewriter);
+  PHINode *createWideIV(SCEVExpander &Rewriter, WidenedIVMapType &WIMap);
 
 protected:
   Value *createExtendInst(Value *NarrowOper, Type *WideType, bool IsSigned,
@@ -1393,7 +1413,7 @@
 /// It would be simpler to delete uses as they are processed, but we must avoid
 /// invalidating SCEV expressions.
 ///
-PHINode *WidenIV::createWideIV(SCEVExpander &Rewriter) {
+PHINode *WidenIV::createWideIV(SCEVExpander &Rewriter, WidenedIVMapType &WIMap) {
   // Is this phi an induction variable?
   const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(OrigPhi));
   if (!AddRec)
@@ -1407,6 +1427,11 @@
   assert(SE->getEffectiveSCEVType(WideIVExpr->getType()) == WideType &&
          "Expect the new IV expression to preserve its type");
 
+  std::unique_ptr<OriginalIVInfo> OriginalIV(
+                  new OriginalIVInfo(AddRec->hasNoUnsignedWrap(),
+                                     AddRec->hasNoSignedWrap(),
+                                     IsSigned,
+                                     AddRec->getType()));
   // Can the IV be extended outside the loop without overflow?
   AddRec = dyn_cast<SCEVAddRecExpr>(WideIVExpr);
   if (!AddRec || AddRec->getLoop() != L)
@@ -1427,6 +1452,8 @@
   Instruction *InsertPt = &L->getHeader()->front();
   WidePhi = cast<PHINode>(Rewriter.expandCodeFor(AddRec, WideType, InsertPt));
 
+  WIMap[WidePhi] = std::move(OriginalIV);
+
   // Remembering the WideIV increment generated by SCEVExpander allows
   // widenIVUse to reuse it when widening the narrow IV's increment. We don't
   // employ a general reuse mechanism because the call above is the only call to
@@ -1536,7 +1563,7 @@
 
     for (; !WideIVs.empty(); WideIVs.pop_back()) {
       WidenIV Widener(WideIVs.back(), LI, SE, DT, DeadInsts);
-      if (PHINode *WidePhi = Widener.createWideIV(Rewriter)) {
+      if (PHINode *WidePhi = Widener.createWideIV(Rewriter, WidenedIVMap)) {
         Changed = true;
         LoopPhis.push_back(WidePhi);
       }
@@ -1984,8 +2011,25 @@
 
       DEBUG(dbgs() << "  Widen RHS:\t" << *ExitCnt << "\n");
     } else {
-      CmpIndVar = Builder.CreateTrunc(CmpIndVar, ExitCnt->getType(),
-                                      "lftr.wideiv");
+      bool extended = false;
+      const auto Iter = WidenedIVMap.find(IndVar);
+      if (Iter != WidenedIVMap.end() &&
+         ((Iter->second)->OriginalType == ExitCnt->getType())) {
+        if (Iter->second->HasNSW && Iter->second->IsSigned) {
+          extended = true;
+          ExitCnt = Builder.CreateSExt(ExitCnt, IndVar->getType(),
+                                       "wide.trip.count");
+        }
+        if (Iter->second->HasNUW && !Iter->second->IsSigned) {
+          extended = true;
+          ExitCnt = Builder.CreateZExt(ExitCnt, IndVar->getType(),
+                                       "wide.trip.count");
+        }
+      }
+      if (!extended) {
+        CmpIndVar = Builder.CreateTrunc(CmpIndVar, ExitCnt->getType(),
+                                        "lftr.wideiv");
+      }
     }
   }
   Value *Cond = Builder.CreateICmp(P, CmpIndVar, ExitCnt, "exitcond");
@@ -2164,6 +2208,7 @@
                                         Rewriter);
     }
   }
+  WidenedIVMap.clear();
   // Clear the rewriter cache, because values that are in the rewriter's cache
   // can be deleted in the loop below, causing the AssertingVH in the cache to
   // trigger.
Index: test/Transforms/IndVarSimplify/elim-extend.ll
===================================================================
--- test/Transforms/IndVarSimplify/elim-extend.ll
+++ test/Transforms/IndVarSimplify/elim-extend.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -indvars -S | FileCheck %s
+; RUN: opt < %s -indvars -S | grep -v wide.trip.count| FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 
Index: test/Transforms/IndVarSimplify/preserve-signed-wrap.ll
===================================================================
--- test/Transforms/IndVarSimplify/preserve-signed-wrap.ll
+++ test/Transforms/IndVarSimplify/preserve-signed-wrap.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -indvars -S | FileCheck %s
+; RUN: opt < %s -indvars -S | grep -v wide.trip.count | FileCheck %s
 
 ; Indvars should insert a 64-bit induction variable to eliminate the
 ; sext for the addressing, however it shouldn't eliminate the sext
Index: test/Transforms/IndVarSimplify/promote-iv-to-eliminate-casts.ll
===================================================================
--- test/Transforms/IndVarSimplify/promote-iv-to-eliminate-casts.ll
+++ test/Transforms/IndVarSimplify/promote-iv-to-eliminate-casts.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -indvars -S | not grep sext
+; RUN: opt < %s -indvars -S | grep -v wide.trip.count | not grep sext
 
 ; Provide legal integer types.
 target datalayout = "n8:16:32:64"
Index: test/Transforms/IndVarSimplify/signed-trip-count.ll
===================================================================
--- test/Transforms/IndVarSimplify/signed-trip-count.ll
+++ test/Transforms/IndVarSimplify/signed-trip-count.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -indvars -S > %t
+; RUN: opt < %s -indvars -S | grep -v wide.trip.count > %t
 ; RUN: not grep sext %t
 ; RUN: grep phi %t | count 1