DirectXHelper updated with IsPowerOf2

Inc/DirectXHelpers.h

@@ -219,26 +219,30 @@ namespace DirectX
         std::vector<D3D12_RESOURCE_BARRIER> mBarriers;
     };
 
+    // Helper to check for power-of-2
+    template<typename T>
+    constexpr bool IsPowerOf2(T x) noexcept { return ((x != 0) && !(x & (x - 1))); }
+
     // Helpers for aligning values by a power of 2
     template<typename T>
-    inline T AlignDown(T size, size_t alignment) noexcept
+    constexpr inline T AlignDown(T size, size_t alignment) noexcept
     {
         if (alignment > 0)
         {
             assert(((alignment - 1) & alignment) == 0);
-            T mask = static_cast<T>(alignment - 1);
+            auto mask = static_cast<T>(alignment - 1);
             return size & ~mask;
         }
         return size;
     }
 
     template<typename T>
-    inline T AlignUp(T size, size_t alignment) noexcept
+    constexpr inline T AlignUp(T size, size_t alignment) noexcept
     {
         if (alignment > 0)
         {
             assert(((alignment - 1) & alignment) == 0);
-            T mask = static_cast<T>(alignment - 1);
+            auto mask = static_cast<T>(alignment - 1);
             return (size + mask) & ~mask;
         }
         return size;