diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index ccfc0b844c3..432a5ef03cd 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -67,10 +67,15 @@ using namespace llvm;
 
 STATISTIC(NumInstRemoved, "Number of instructions removed");
 STATISTIC(NumDeadBlocks , "Number of basic blocks unreachable");
+STATISTIC(NumInstReplaced,
+          "Number of instructions replaced with (simpler) instruction");
 
 STATISTIC(IPNumInstRemoved, "Number of instructions removed by IPSCCP");
 STATISTIC(IPNumArgsElimed ,"Number of arguments constant propagated by IPSCCP");
 STATISTIC(IPNumGlobalConst, "Number of globals found to be constant by IPSCCP");
+STATISTIC(
+    IPNumInstReplaced,
+    "Number of instructions replaced with (simpler) instruction by IPSCCP");
 
 // The maximum number of range extensions allowed for operations requiring
 // widening.
@@ -283,6 +288,8 @@ public:
     return StructValues;
   }
 
+  void removeLatticeValueFor(Value *V) { ValueState.erase(V); }
+
   const ValueLatticeElement &getLatticeValueFor(Value *V) const {
     assert(!V->getType()->isStructTy() &&
            "Should use getStructLatticeValueFor");
@@ -1607,7 +1614,9 @@ static bool tryToReplaceWithConstant(SCCPSolver &Solver, Value *V) {
 }
 
 static bool simplifyInstsInBlock(SCCPSolver &Solver, BasicBlock &BB,
-                                 Statistic &InstRemovedStat) {
+                                 SmallPtrSetImpl<Value *> &InsertedValues,
+                                 Statistic &InstRemovedStat,
+                                 Statistic &InstReplacedStat) {
   bool MadeChanges = false;
   for (Instruction &Inst : make_early_inc_range(BB)) {
     if (Inst.getType()->isVoidTy())
@@ -1618,6 +1627,22 @@ static bool simplifyInstsInBlock(SCCPSolver &Solver, BasicBlock &BB,
       // Hey, we just changed something!
       MadeChanges = true;
       ++InstRemovedStat;
+    } else if (isa<SExtInst>(&Inst)) {
+      Value *ExtOp = Inst.getOperand(0);
+      if (isa<Constant>(ExtOp) || InsertedValues.count(ExtOp))
+        continue;
+      const ValueLatticeElement &IV = Solver.getLatticeValueFor(ExtOp);
+      if (!IV.isConstantRange(/*UndefAllowed=*/false))
+        continue;
+      if (IV.getConstantRange().isAllNonNegative()) {
+        auto *ZExt = new ZExtInst(ExtOp, Inst.getType(), "", &Inst);
+        InsertedValues.insert(ZExt);
+        Inst.replaceAllUsesWith(ZExt);
+        Solver.removeLatticeValueFor(&Inst);
+        Inst.eraseFromParent();
+        InstReplacedStat++;
+        MadeChanges = true;
+      }
     }
   }
   return MadeChanges;
@@ -1653,6 +1678,7 @@ static bool runSCCP(Function &F, const DataLayout &DL,
   // delete their contents now.  Note that we cannot actually delete the blocks,
   // as we cannot modify the CFG of the function.
 
+  SmallPtrSet<Value *, 32> InsertedValues;
   for (BasicBlock &BB : F) {
     if (!Solver.isBlockExecutable(&BB)) {
       LLVM_DEBUG(dbgs() << "  BasicBlock Dead:" << BB);
@@ -1664,7 +1690,8 @@ static bool runSCCP(Function &F, const DataLayout &DL,
       continue;
     }
 
-    MadeChanges |= simplifyInstsInBlock(Solver, BB, NumInstRemoved);
+    MadeChanges |= simplifyInstsInBlock(Solver, BB, InsertedValues,
+                                        NumInstRemoved, NumInstReplaced);
   }
 
   return MadeChanges;
@@ -1893,6 +1920,7 @@ bool llvm::runIPSCCP(
         }
       }
 
+    SmallPtrSet<Value *, 32> InsertedValues;
     for (BasicBlock &BB : F) {
       if (!Solver.isBlockExecutable(&BB)) {
         LLVM_DEBUG(dbgs() << "  BasicBlock Dead:" << BB);
@@ -1905,7 +1933,8 @@ bool llvm::runIPSCCP(
         continue;
       }
 
-      MadeChanges |= simplifyInstsInBlock(Solver, BB, IPNumInstRemoved);
+      MadeChanges |= simplifyInstsInBlock(Solver, BB, InsertedValues,
+                                          IPNumInstRemoved, IPNumInstReplaced);
     }
 
     DomTreeUpdater DTU = Solver.getDTU(F);
diff --git a/test/Transforms/SCCP/ip-ranges-casts.ll b/test/Transforms/SCCP/ip-ranges-casts.ll
index c7a53c11897..b39f2985b8a 100644
--- a/test/Transforms/SCCP/ip-ranges-casts.ll
+++ b/test/Transforms/SCCP/ip-ranges-casts.ll
@@ -109,9 +109,9 @@ define i1 @caller.zext() {
 ; x = [100, 301)
 define internal i1 @f.sext(i32 %x, i32 %y) {
 ; CHECK-LABEL: define internal i1 @f.sext(i32 %x, i32 %y) {
-; CHECK-NEXT:    %t.1 = sext i32 %x to i64
-; CHECK-NEXT:    %c.2 = icmp sgt i64 %t.1, 299
-; CHECK-NEXT:    %c.4 = icmp slt i64 %t.1, 101
+; CHECK-NEXT:    [[T_1:%.*]] = zext i32 %x to i64
+; CHECK-NEXT:    %c.2 = icmp sgt i64 [[T_1]], 299
+; CHECK-NEXT:    %c.4 = icmp slt i64 [[T_1]], 101
 ; CHECK-NEXT:    %res.1 = add i1 false, %c.2
 ; CHECK-NEXT:    %res.2 = add i1 %res.1, false
 ; CHECK-NEXT:    %res.3 = add i1 %res.2, %c.4
diff --git a/test/Transforms/SCCP/ip-ranges-sext.ll b/test/Transforms/SCCP/ip-ranges-sext.ll
index eeac47ae572..aef562cfdb5 100644
--- a/test/Transforms/SCCP/ip-ranges-sext.ll
+++ b/test/Transforms/SCCP/ip-ranges-sext.ll
@@ -105,8 +105,8 @@ exit:
 define i64 @test5(i32 %x) {
 ; CHECK-LABEL: @test5(
 ; CHECK-NEXT:    [[P:%.*]] = and i32 [[X:%.*]], 15
-; CHECK-NEXT:    [[EXT:%.*]] = sext i32 [[P]] to i64
-; CHECK-NEXT:    ret i64 [[EXT]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[P]] to i64
+; CHECK-NEXT:    ret i64 [[TMP1]]
 ;
   %p = and i32 %x, 15
   %ext = sext i32 %p to i64
@@ -126,8 +126,8 @@ define i64 @test6(i32 %x) {
 define i64 @test7(i16 %x) {
 ; CHECK-LABEL: @test7(
 ; CHECK-NEXT:    [[P:%.*]] = and i16 [[X:%.*]], 15
-; CHECK-NEXT:    [[EXT_1:%.*]] = sext i16 [[P]] to i32
-; CHECK-NEXT:    [[EXT_2:%.*]] = sext i32 [[EXT_1]] to i64
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i16 [[P]] to i32
+; CHECK-NEXT:    [[EXT_2:%.*]] = sext i32 [[TMP1]] to i64
 ; CHECK-NEXT:    ret i64 [[EXT_2]]
 ;
   %p = and i16 %x, 15
diff --git a/test/Transforms/SCCP/ranges-sext.ll b/test/Transforms/SCCP/ranges-sext.ll
index 66e9e52c044..75e070b0162 100644
--- a/test/Transforms/SCCP/ranges-sext.ll
+++ b/test/Transforms/SCCP/ranges-sext.ll
@@ -35,8 +35,8 @@ exit:
 define i64 @test2(i32 %x) {
 ; CHECK-LABEL: @test2(
 ; CHECK-NEXT:    [[P:%.*]] = and i32 [[X:%.*]], 15
-; CHECK-NEXT:    [[EXT:%.*]] = sext i32 [[P]] to i64
-; CHECK-NEXT:    ret i64 [[EXT]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[P]] to i64
+; CHECK-NEXT:    ret i64 [[TMP1]]
 ;
   %p = and i32 %x, 15
   %ext = sext i32 %p to i64
@@ -54,8 +54,8 @@ define i64 @test3(i1 %c.1, i1 %c.2) {
 ; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[P:%.*]] = phi i32 [ 0, [[TRUE_1]] ], [ 1, [[TRUE_2]] ], [ 3, [[FALSE]] ]
-; CHECK-NEXT:    [[EXT:%.*]] = sext i32 [[P]] to i64
-; CHECK-NEXT:    ret i64 [[EXT]]
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[P]] to i64
+; CHECK-NEXT:    ret i64 [[TMP1]]
 ;
   br i1 %c.1, label %true.1, label %false
 
diff --git a/test/Transforms/SCCP/widening.ll b/test/Transforms/SCCP/widening.ll
index 825175882b1..2703bdb27df 100644
--- a/test/Transforms/SCCP/widening.ll
+++ b/test/Transforms/SCCP/widening.ll
@@ -451,7 +451,7 @@ define void @foo(i64* %arg) {
 ; SCCP-NEXT:    [[TMP7:%.*]] = sub i64 3, [[TMP6]]
 ; SCCP-NEXT:    [[TMP8:%.*]] = shl i64 [[TMP7]], 1
 ; SCCP-NEXT:    [[TMP9:%.*]] = trunc i64 [[TMP8]] to i32
-; SCCP-NEXT:    [[TMP10:%.*]] = sext i32 [[TMP9]] to i64
+; SCCP-NEXT:    [[TMP10:%.*]] = zext i32 [[TMP9]] to i64
 ; SCCP-NEXT:    br label [[BB11:%.*]]
 ; SCCP:       bb11:
 ; SCCP-NEXT:    [[TMP12:%.*]] = phi i64 [ [[TMP10]], [[BB4]] ], [ [[TMP17:%.*]], [[BB18:%.*]] ]
@@ -489,7 +489,7 @@ define void @foo(i64* %arg) {
 ; IPSCCP-NEXT:    [[TMP7:%.*]] = sub i64 3, [[TMP6]]
 ; IPSCCP-NEXT:    [[TMP8:%.*]] = shl i64 [[TMP7]], 1
 ; IPSCCP-NEXT:    [[TMP9:%.*]] = trunc i64 [[TMP8]] to i32
-; IPSCCP-NEXT:    [[TMP10:%.*]] = sext i32 [[TMP9]] to i64
+; IPSCCP-NEXT:    [[TMP10:%.*]] = zext i32 [[TMP9]] to i64
 ; IPSCCP-NEXT:    br label [[BB11:%.*]]
 ; IPSCCP:       bb11:
 ; IPSCCP-NEXT:    [[TMP12:%.*]] = phi i64 [ [[TMP10]], [[BB4]] ], [ [[TMP17:%.*]], [[BB18:%.*]] ]