PVS-Studio warning V519 for Scilab

int C2F(pmatj) (char *fname, int *lw, int *j,
                unsigned long fname_len)
{
  ....
  ix1 = il2 + 4;
  m2 = Max(m, 1);
  ix1 = il + 9 + m * n;
  ....
}

This suspicious code was found in Scilab project by PVS-Studio static code analyzer.
Warning message is:
V519 The 'ix1' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 2387, 2389. stack1.c 2389

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/