libavcodec/vp8dsp.c:165: error: Uninitialized Value
  The value read from q0 was never initialized.

libavcodec/vp8dsp.c:165:5: 
163.     const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;
164. 
165.     a = 3*(q0 - p0);
         ^
166. 
167.     if (is4tap)

static av_always_inline void filter_common(uint8_t *p, ptrdiff_t stride, int is4tap)
{
    LOAD_PIXELS
    int a, f1, f2;
    const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;
    a = 3*(q0 - p0);
    if (is4tap)
        a += clip_int8(p1 - q1);
    a = clip_int8(a);
    f1 = FFMIN(a+4, 127) >> 3;
    f2 = FFMIN(a+3, 127) >> 3;
    p[-1*stride] = cm[p0 + f2];
    p[ 0*stride] = cm[q0 - f1];
    if (!is4tap) {
        a = (f1+1)>>1;
        p[-2*stride] = cm[p1 + a];
        p[ 1*stride] = cm[q1 - a];
    }
}
['static av_always_inline void filter_common(uint8_t *p, ptrdiff_t stride, int is4tap)\n{\n    LOAD_PIXELS\n    int a, f1, f2;\n    const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;\n    a = 3*(q0 - p0);\n    if (is4tap)\n        a += clip_int8(p1 - q1);\n    a = clip_int8(a);\n    f1 = FFMIN(a+4, 127) >> 3;\n    f2 = FFMIN(a+3, 127) >> 3;\n    p[-1*stride] = cm[p0 + f2];\n    p[ 0*stride] = cm[q0 - f1];\n    if (!is4tap) {\n        a = (f1+1)>>1;\n        p[-2*stride] = cm[p1 + a];\n        p[ 1*stride] = cm[q1 - a];\n    }\n}']