PVS-Studio warning V640 for FFMpeg

static void vc1_interp_mc(VC1Context *v)
{
  ....
  if (v->field_mode) {
      if (v->cur_field_type != v->ref_field_type[1])
          my   = my   - 2 + 4 * v->cur_field_type;
          uvmy = uvmy - 2 + 4 * v->cur_field_type;
  }
  ....
}

This suspicious code was found in FFMpeg project by PVS-Studio static code analyzer.
Warning message is:
V640 The code's operational logic does not correspond with its formatting. The statement is indented to the right, but it is always executed. It is possible that curly brackets are missing. vc1dec.c 1917

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/