Consolidate implementation of Rotate and PopCount

src/System.Private.CoreLib/shared/System/Buffers/Text/FormattingHelpers.CountDigits.cs

@@ -103,11 +103,9 @@ public static int CountDigits(uint value)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int CountHexDigits(ulong value)
         {
-            int right = 64 - BitOps.LeadingZeroCount(value | 1);
-            return (right + 3) >> 2;
+            return (64 - BitOps.LeadingZeroCount(value | 1) + 3) >> 2;
         }
 
-
         // Counts the number of trailing '0' digits in a decimal number.
         // e.g., value =      0 => retVal = 0, valueWithoutTrailingZeros = 0
         //       value =   1234 => retVal = 0, valueWithoutTrailingZeros = 1234

src/System.Private.CoreLib/shared/System/HashCode.cs

@@ -264,17 +264,13 @@ private static void Initialize(out uint v1, out uint v2, out uint v3, out uint v
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint Round(uint hash, uint input)
         {
-            hash += input * Prime2;
-            hash = BitOps.RotateLeft(hash, 13);
-            hash *= Prime1;
-            return hash;
+            return BitOps.RotateLeft(hash + input * Prime2, 13) * Prime1;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint QueueRound(uint hash, uint queuedValue)
         {
-            hash += queuedValue * Prime3;
-            return BitOps.RotateLeft(hash, 17) * Prime4;
+            return BitOps.RotateLeft(hash + queuedValue * Prime3, 17) * Prime4;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]