diff --git a/llvm/include/llvm/ADT/Statistic.h b/llvm/include/llvm/ADT/Statistic.h
--- a/llvm/include/llvm/ADT/Statistic.h
+++ b/llvm/include/llvm/ADT/Statistic.h
@@ -53,7 +53,7 @@
   const char *const Name;
   const char *const Desc;
 
-  std::atomic<unsigned> Value;
+  std::atomic<uint64_t> Value;
   std::atomic<bool> Initialized;
 
   constexpr TrackingStatistic(const char *DebugType, const char *Name,
@@ -65,12 +65,12 @@
   const char *getName() const { return Name; }
   const char *getDesc() const { return Desc; }
 
-  unsigned getValue() const { return Value.load(std::memory_order_relaxed); }
+  uint64_t getValue() const { return Value.load(std::memory_order_relaxed); }
 
   // Allow use of this class as the value itself.
-  operator unsigned() const { return getValue(); }
+  operator uint64_t() const { return getValue(); }
 
-  const TrackingStatistic &operator=(unsigned Val) {
+  const TrackingStatistic &operator=(uint64_t Val) {
     Value.store(Val, std::memory_order_relaxed);
     return init();
   }
@@ -95,22 +95,22 @@
     return Value.fetch_sub(1, std::memory_order_relaxed);
   }
 
-  const TrackingStatistic &operator+=(unsigned V) {
+  const TrackingStatistic &operator+=(uint64_t V) {
     if (V == 0)
       return *this;
     Value.fetch_add(V, std::memory_order_relaxed);
     return init();
   }
 
-  const TrackingStatistic &operator-=(unsigned V) {
+  const TrackingStatistic &operator-=(uint64_t V) {
     if (V == 0)
       return *this;
     Value.fetch_sub(V, std::memory_order_relaxed);
     return init();
   }
 
-  void updateMax(unsigned V) {
-    unsigned PrevMax = Value.load(std::memory_order_relaxed);
+  void updateMax(uint64_t V) {
+    uint64_t PrevMax = Value.load(std::memory_order_relaxed);
     // Keep trying to update max until we succeed or another thread produces
     // a bigger max than us.
     while (V > PrevMax && !Value.compare_exchange_weak(
@@ -200,7 +200,7 @@
 /// during it's execution. It will return the value at the point that it is
 /// read. However, it will prevent new statistics from registering until it
 /// completes.
-const std::vector<std::pair<StringRef, unsigned>> GetStatistics();
+const std::vector<std::pair<StringRef, uint64_t>> GetStatistics();
 
 /// Reset the statistics. This can be used to zero and de-register the
 /// statistics in order to measure a compilation.
diff --git a/llvm/lib/Support/Statistic.cpp b/llvm/lib/Support/Statistic.cpp
--- a/llvm/lib/Support/Statistic.cpp
+++ b/llvm/lib/Support/Statistic.cpp
@@ -192,7 +192,7 @@
 
   // Print all of the statistics.
   for (TrackingStatistic *Stat : Stats.Stats)
-    OS << format("%*u %-*s - %s\n", MaxValLen, Stat->getValue(),
+    OS << format("%*" PRIu64 " %-*s - %s\n", MaxValLen, Stat->getValue(),
                  MaxDebugTypeLen, Stat->getDebugType(), Stat->getDesc());
 
   OS << '\n';  // Flush the output stream.
@@ -253,9 +253,9 @@
 #endif
 }
 
-const std::vector<std::pair<StringRef, unsigned>> llvm::GetStatistics() {
+const std::vector<std::pair<StringRef, uint64_t>> llvm::GetStatistics() {
   sys::SmartScopedLock<true> Reader(*StatLock);
-  std::vector<std::pair<StringRef, unsigned>> ReturnStats;
+  std::vector<std::pair<StringRef, uint64_t>> ReturnStats;
 
   for (const auto &Stat : StatInfo->statistics())
     ReturnStats.emplace_back(Stat->getName(), Stat->getValue());
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp
--- a/llvm/lib/Transforms/Scalar/NewGVN.cpp
+++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp
@@ -3351,7 +3351,7 @@
 // instruction set, propagating value numbers, marking things touched, etc,
 // until the set of touched instructions is completely empty.
 void NewGVN::iterateTouchedInstructions() {
-  unsigned int Iterations = 0;
+  uint64_t Iterations = 0;
   // Figure out where touchedinstructions starts
   int FirstInstr = TouchedInstructions.find_first();
   // Nothing set, nothing to iterate, just return.
diff --git a/llvm/unittests/ADT/StatisticTest.cpp b/llvm/unittests/ADT/StatisticTest.cpp
--- a/llvm/unittests/ADT/StatisticTest.cpp
+++ b/llvm/unittests/ADT/StatisticTest.cpp
@@ -11,7 +11,7 @@
 #include "gtest/gtest.h"
 using namespace llvm;
 
-using OptionalStatistic = Optional<std::pair<StringRef, unsigned>>;
+using OptionalStatistic = Optional<std::pair<StringRef, uint64_t>>;
 
 namespace {
 #define DEBUG_TYPE "unittest"
@@ -21,7 +21,7 @@
 
 #if LLVM_ENABLE_STATS
 static void
-extractCounters(const std::vector<std::pair<StringRef, unsigned>> &Range,
+extractCounters(const std::vector<std::pair<StringRef, uint64_t>> &Range,
                 OptionalStatistic &S1, OptionalStatistic &S2) {
   for (const auto &S : Range) {
     if (S.first == "Counter")
@@ -36,20 +36,21 @@
   EnableStatistics();
 
   Counter = 0;
-  EXPECT_EQ(Counter, 0u);
+  EXPECT_EQ(Counter, 0ull);
   Counter++;
   Counter++;
+  Counter += (std::numeric_limits<uint64_t>::max() - 3);
 #if LLVM_ENABLE_STATS
-  EXPECT_EQ(Counter, 2u);
+  EXPECT_EQ(Counter, std::numeric_limits<uint64_t>::max() - 1);
 #else
-  EXPECT_EQ(Counter, 0u);
+  EXPECT_EQ(Counter, 0ull);
 #endif
 
   AlwaysCounter = 0;
-  EXPECT_EQ(AlwaysCounter, 0u);
+  EXPECT_EQ(AlwaysCounter, 0ull);
   AlwaysCounter++;
   ++AlwaysCounter;
-  EXPECT_EQ(AlwaysCounter, 2u);
+  EXPECT_EQ(AlwaysCounter, 2ull);
 }
 
 TEST(StatisticTest, Assign) {