Eliminate left shift of negative value by using multiplication instead

webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc

 /*
  *  Copyright (c) 2012 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 177 matching lines @@
     int16_t temp_val_high = ((coeff2_ * sample_history2_[1] + 8192) >> 14)
         - sample_history2_[0];
 
     // Update recursion memory.
     sample_history1_[0] = sample_history1_[1];
     sample_history1_[1] = temp_val_low;
     sample_history2_[0] = sample_history2_[1];
     sample_history2_[1] = temp_val_high;
 
     // Attenuate the low frequency tone 3 dB.
-    int32_t temp_val = kAmpMultiplier * temp_val_low + (temp_val_high << 15);
+    int32_t temp_val =
+        kAmpMultiplier * temp_val_low + temp_val_high * (1 << 15);
     // Normalize the signal to Q14 with proper rounding.
     temp_val = (temp_val + 16384) >> 15;
     // Scale the signal to correct volume.
     (*output)[0][i] =
         static_cast<int16_t>((temp_val * amplitude_ + 8192) >> 14);
   }
   // Copy first channel to all other channels.
   for (size_t channel = 1; channel < output->Channels(); ++channel) {
     output->CopyChannel(0, channel);
   }
 
   return static_cast<int>(num_samples);
 }
 
 bool DtmfToneGenerator::initialized() const {
   return initialized_;
 }
 
 }  // namespace webrtc