Remove some unnecessary #if TARGET_64BIT (#118361)

Author: xtqqczze

src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerServices/FunctionPointerOps.cs

@@ -88,11 +88,7 @@ public static unsafe IntPtr GetGenericMethodFunctionPointer(IntPtr canonFunction
         public static unsafe bool IsGenericMethodPointer(IntPtr functionPointer)
         {
             // Check the low bit to find out what kind of function pointer we have here.
-#if TARGET_64BIT
-            if ((functionPointer.ToInt64() & FatFunctionPointerOffset) == FatFunctionPointerOffset)
-#else
-            if ((functionPointer.ToInt32() & FatFunctionPointerOffset) == FatFunctionPointerOffset)
-#endif
+            if ((functionPointer & FatFunctionPointerOffset) == FatFunctionPointerOffset)
             {
                 return true;
             }

src/libraries/System.Private.CoreLib/src/System/Double.cs

@@ -1450,13 +1450,8 @@ private static bool TryConvertTo<TOther>(double value, [MaybeNullWhen(false)] ou
             else if (typeof(TOther) == typeof(nuint))
             {
 #if MONO
-#if TARGET_64BIT
-                nuint actualResult = (value >= ulong.MaxValue) ? unchecked((nuint)ulong.MaxValue) :
-                                     (value <= ulong.MinValue) ? unchecked((nuint)ulong.MinValue) : (nuint)value;
-#else
-                nuint actualResult = (value >= uint.MaxValue) ? uint.MaxValue :
-                                     (value <= uint.MinValue) ? uint.MinValue : (nuint)value;
-#endif
+                nuint actualResult = (value >= nuint.MaxValue) ? nuint.MaxValue :
+                                     (value <= nuint.MinValue) ? nuint.MinValue : (nuint)value;
 #else
                 nuint actualResult = (nuint)value;
 #endif

src/libraries/System.Private.CoreLib/src/System/Single.cs

@@ -1469,13 +1469,8 @@ private static bool TryConvertTo<TOther>(float value, [MaybeNullWhen(false)] out
             else if (typeof(TOther) == typeof(nuint))
             {
 #if MONO
-#if TARGET_64BIT
-                nuint actualResult = (value >= ulong.MaxValue) ? unchecked((nuint)ulong.MaxValue) :
-                                     (value <= ulong.MinValue) ? unchecked((nuint)ulong.MinValue) : (nuint)value;
-#else
-                nuint actualResult = (value >= uint.MaxValue) ? uint.MaxValue :
-                                     (value <= uint.MinValue) ? uint.MinValue : (nuint)value;
-#endif
+                nuint actualResult = (value >= nuint.MaxValue) ? nuint.MaxValue :
+                                     (value <= nuint.MinValue) ? nuint.MinValue : (nuint)value;
 #else
                 nuint actualResult = (nuint)value;
 #endif

src/libraries/System.Private.CoreLib/src/System/UIntPtr.cs

@@ -486,13 +486,8 @@ bool IBinaryInteger<nuint>.TryWriteLittleEndian(Span<byte> destination, out int
         /// <inheritdoc cref="IBinaryNumber{TSelf}.AllBitsSet" />
         static nuint IBinaryNumber<nuint>.AllBitsSet
         {
-#if TARGET_64BIT
-            [NonVersionable]
-            get => unchecked((nuint)0xFFFF_FFFF_FFFF_FFFF);
-#else
             [NonVersionable]
-            get => (nuint)0xFFFF_FFFF;
-#endif
+            get => unchecked((nuint)nuint_t.MaxValue);
         }
 
         /// <inheritdoc cref="IBinaryNumber{TSelf}.IsPow2(TSelf)" />