static inline int16_t shrink_func(int16_t p1p, int16_t p1n,
                                  int16_t z0p, int16_t z0n,
                                  int16_t n1p, int16_t n1n)
{
    /*
    return (1 * p1p + 5 * p1n + 10 * z0p + 10 * z0n + 5 * n1p + 1 * n1n + 16) >> 5;
    */
    int32_t r = (p1p + p1n + n1p + n1n) >> 1;
    r = (r + z0p + z0n) >> 1;
    r = (r + p1n + n1p) >> 1;
    return (r + z0p + z0n + 2) >> 2;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.