PVS-Studio warning V501 for VTK

template <class iterT>
void vtkDataSetAttributesCopyValues(....)
{
  ...
  inZPtr +=
    (outExt[0]-outExt[0])*inIncs[0] * data_type_size +
    (outExt[2] - outExt[2])*inIncs[1] * data_type_size +
    (outExt[4] - outExt[4])*inIncs[2] * data_type_size;
  ...
}

Meaningless code. It's equivalent to inZPtr += 0;

This suspicious code was found in VTK project by PVS-Studio static code analyzer.
Warning message is:
V501 There are identical sub-expressions to the left and to the right of the '-' operator: outExt[0] - outExt[0] vtkFiltering vtkdatasetattributes.cxx 457

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/