libavcodec/flac.c:309: error: Uninitialized Value
  The value read from b was never initialized.

libavcodec/flac.c:309:35: 
307.         case 4:
308.             for (i = pred_order; i < blocksize; i++)
309.                 decoded[i] = a += b += c += d += decoded[i];
                                       ^
310.             break;
311.         default:
