libavcodec/opus_silk.c:1037: error: Integer Overflow L2
  ([0, +oo] - 4):unsigned32.

libavcodec/opus_silk.c:1037:21: <LHS trace>
1035.         int index = s->wb ? silk_lsf_s2_model_sel_wb  [lsf_i1][i] :
1036.                             silk_lsf_s2_model_sel_nbmb[lsf_i1][i];
1037.         lsf_i2[i] = opus_rc_getsymbol(rc, silk_model_lsf_s2[index]) - 4;
                          ^
1038.         if (lsf_i2[i] == -4)
1039.             lsf_i2[i] -= opus_rc_getsymbol(rc, silk_model_lsf_s2_ext);

libavcodec/opus_silk.c:1037:21: Call
1035.         int index = s->wb ? silk_lsf_s2_model_sel_wb  [lsf_i1][i] :
1036.                             silk_lsf_s2_model_sel_nbmb[lsf_i1][i];
1037.         lsf_i2[i] = opus_rc_getsymbol(rc, silk_model_lsf_s2[index]) - 4;
                          ^
1038.         if (lsf_i2[i] == -4)
1039.             lsf_i2[i] -= opus_rc_getsymbol(rc, silk_model_lsf_s2_ext);

libavcodec/opus.h:208:10: Assignment
  206.     symbol = total - FFMIN(symbol, total);
  207. 
  208.     for (k = 0; cdf[k] <= symbol; k++);
                ^
  209.     high = cdf[k];
  210.     low  = k ? cdf[k-1] : 0;

libavcodec/opus.h:214:5: Assignment
  212.     opus_rc_update(rc, scale, low, high, total);
  213. 
  214.     return k;
           ^
  215. }
  216. 

libavcodec/opus_silk.c:1037:9: Binary operation: ([0, +oo] - 4):unsigned32
1035.         int index = s->wb ? silk_lsf_s2_model_sel_wb  [lsf_i1][i] :
1036.                             silk_lsf_s2_model_sel_nbmb[lsf_i1][i];
1037.         lsf_i2[i] = opus_rc_getsymbol(rc, silk_model_lsf_s2[index]) - 4;
              ^
1038.         if (lsf_i2[i] == -4)
1039.             lsf_i2[i] -= opus_rc_getsymbol(rc, silk_model_lsf_s2_ext);
