     }
     else if encoded.count == 1
       && !(arg is _CVarArgPassedAsDouble)
-      && gpRegistersUsed < _x86_64CountGPRegisters {
+      && gpRegistersUsed < _countGPRegisters {
       storage[gpRegistersUsed] = encoded[0]
       gpRegistersUsed += 1
     }

  /// appropriately interpreted by C varargs.
  @_inlineable // FIXME(sil-serialize-all)
  public var _cVarArgEncoding: [Int] {
    return _encodeBitsAsWords(self)
  }
}


  @_versioned // FIXME(sil-serialize-all)
  internal init() {
    // prepare the register save area
    storage = ContiguousArray(repeating: 0, count: _registerSaveWords)
  }

  @_inlineable // FIXME(sil-serialize-all)
