Fix UBSan errors (left shift of negative value)

webrtc/modules/audio_coding/codecs/ilbc/hp_output.c

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 30 matching lines @@
     /*
       y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2]
       + (-a[1])*y[i-1] + (-a[2])*y[i-2];
     */
 
     tmpW32 = y[1] * ba[3];  /* (-a[1])*y[i-1] (low part) */
     tmpW32 += y[3] * ba[4];  /* (-a[2])*y[i-2] (low part) */
     tmpW32 = (tmpW32>>15);
     tmpW32 += y[0] * ba[3];  /* (-a[1])*y[i-1] (high part) */
     tmpW32 += y[2] * ba[4];  /* (-a[2])*y[i-2] (high part) */
-    tmpW32 = (tmpW32<<1);
+    tmpW32 *= 2;
 
     tmpW32 += signal[i] * ba[0];  /* b[0]*x[0] */
     tmpW32 += x[0] * ba[1];  /* b[1]*x[i-1] */
     tmpW32 += x[1] * ba[2];  /* b[2]*x[i-2] */
 
     /* Update state (input part) */
     x[1] = x[0];
     x[0] = signal[i];
 
     /* Rounding in Q(12-1), i.e. add 2^10 */
     tmpW32b = tmpW32 + 1024;
 
     /* Saturate (to 2^26) so that the HP filtered signal does not overflow */
     tmpW32b = WEBRTC_SPL_SAT((int32_t)67108863, tmpW32b, (int32_t)-67108864);
 
     /* Convert back to Q0 and multiply with 2 */
     signal[i] = (int16_t)(tmpW32b >> 11);
 
     /* Update state (filtered part) */
     y[2] = y[0];
     y[3] = y[1];
 
     /* upshift tmpW32 by 3 with saturation */
     if (tmpW32>268435455) {
       tmpW32 = WEBRTC_SPL_WORD32_MAX;
     } else if (tmpW32<-268435456) {
       tmpW32 = WEBRTC_SPL_WORD32_MIN;
     } else {
-      tmpW32 <<= 3;
+      tmpW32 *= 8;
     }
 
     y[0] = (int16_t)(tmpW32 >> 16);
-    y[1] = (int16_t)((tmpW32 - (y[0] << 16)) >> 1);
+    y[1] = (int16_t)((tmpW32 & 0xffff) >> 1);
 
   }
 
   return;
 }