PVS-Studio warning V501 for IPP Samples

int ec_fb_GetSubbandNum(void *stat)
{
    _fbECState *state=(_fbECState *)stat;
    return (state->freq-state->freq);
}

Something wrong has been subtracted. I don't know what the code should look like exactly, but this is obviously an error. The function always returns 0.

This suspicious code was found in IPP Samples 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: state->freq - state->freq speech ec_fb.c 250

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/