Index: include/llvm/Support/MathExtras.h
===================================================================
--- include/llvm/Support/MathExtras.h
+++ include/llvm/Support/MathExtras.h
@@ -116,7 +116,7 @@
 /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
 ///   valid arguments.
 template <typename T>
-std::size_t countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
+unsigned countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
   static_assert(std::numeric_limits<T>::is_integer &&
                     !std::numeric_limits<T>::is_signed,
                 "Only unsigned integral types are allowed.");
@@ -125,7 +125,7 @@
 
 namespace detail {
 template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter {
-  static std::size_t count(T Val, ZeroBehavior) {
+  static unsigned count(T Val, ZeroBehavior) {
     if (!Val)
       return std::numeric_limits<T>::digits;
 
@@ -144,7 +144,7 @@
 
 #if __GNUC__ >= 4 || defined(_MSC_VER)
 template <typename T> struct LeadingZerosCounter<T, 4> {
-  static std::size_t count(T Val, ZeroBehavior ZB) {
+  static unsigned count(T Val, ZeroBehavior ZB) {
     if (ZB != ZB_Undefined && Val == 0)
       return 32;
 
@@ -160,7 +160,7 @@
 
 #if !defined(_MSC_VER) || defined(_M_X64)
 template <typename T> struct LeadingZerosCounter<T, 8> {
-  static std::size_t count(T Val, ZeroBehavior ZB) {
+  static unsigned count(T Val, ZeroBehavior ZB) {
     if (ZB != ZB_Undefined && Val == 0)
       return 64;
 
@@ -185,7 +185,7 @@
 /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
 ///   valid arguments.
 template <typename T>
-std::size_t countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
+unsigned countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
   static_assert(std::numeric_limits<T>::is_integer &&
                     !std::numeric_limits<T>::is_signed,
                 "Only unsigned integral types are allowed.");
@@ -458,7 +458,7 @@
 /// \param ZB the behavior on an input of all ones. Only ZB_Width and
 /// ZB_Undefined are valid arguments.
 template <typename T>
-std::size_t countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
+unsigned countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
   static_assert(std::numeric_limits<T>::is_integer &&
                     !std::numeric_limits<T>::is_signed,
                 "Only unsigned integral types are allowed.");
@@ -474,7 +474,7 @@
 /// \param ZB the behavior on an input of all ones. Only ZB_Width and
 /// ZB_Undefined are valid arguments.
 template <typename T>
-std::size_t countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
+unsigned countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
   static_assert(std::numeric_limits<T>::is_integer &&
                     !std::numeric_limits<T>::is_signed,
                 "Only unsigned integral types are allowed.");