[Support][MathExtras] Add missing include and disable _BitScan{Forwar…

…d,Reverse}64 on non x64 MSVC systems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182671 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/MathExtras.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_SUPPORT_MATHEXTRAS_H
 #define LLVM_SUPPORT_MATHEXTRAS_H
 
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/SwapByteOrder.h"
 #include "llvm/Support/type_traits.h"
 
@@ -86,6 +87,7 @@ inline std::size_t countTrailingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) {
 #endif
 }
 
+#if !defined(_MSC_VER) || defined(_M_X64)
 template <>
 inline std::size_t countTrailingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
@@ -100,6 +102,7 @@ inline std::size_t countTrailingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
 #endif
 }
 #endif
+#endif
 
 /// \brief Count number of 0's from the most significant bit to the least
 ///   stopping at the first 1.
@@ -148,6 +151,7 @@ inline std::size_t countLeadingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) {
 #endif
 }
 
+#if !defined(_MSC_VER) || defined(_M_X64)
 template <>
 inline std::size_t countLeadingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
@@ -162,6 +166,7 @@ inline std::size_t countLeadingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
 #endif
 }
 #endif
+#endif
 
 /// \brief Get the index of the first set bit starting from the least
 ///   significant bit.