In such situations:

      if(incx.eq.1.and.incy.eq.1)go to 20

   20 do 30 i = 1,n

Change manualy source code to

      if(incx.eq.1.and.incy.eq.1)go to 20

   20 continue
      do 30 i = 1,n

So that 'call mpcdummy' will be in correct place !