iSAC fix: Ignore overflow in signed left shift

webrtc/common_audio/signal_processing/include/signal_processing_library.h

 /*
  *  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 45 matching lines @@
      + ((WEBRTC_SPL_MUL_16_16(a, (b & 0xffff) >> 1) + 0x4000) >> 15))
 #endif
 #endif
 
 #define WEBRTC_SPL_MUL_16_32_RSFT11(a, b)          \
   (WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 5) + \
    (((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x0200) >> 10))
 #define WEBRTC_SPL_MUL_16_32_RSFT14(a, b)          \
   (WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 2) + \
    (((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x1000) >> 13))
-#define WEBRTC_SPL_MUL_16_32_RSFT15(a, b) \
-    ((WEBRTC_SPL_MUL_16_16(a, (b) >> 16) << 1) \
-    + (((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x2000) >> 14))
+#define WEBRTC_SPL_MUL_16_32_RSFT15(a, b)            \
+  ((WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 1)) + \
+   (((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x2000) >> 14))
 
 #define WEBRTC_SPL_MUL_16_16_RSFT(a, b, c) \
     (WEBRTC_SPL_MUL_16_16(a, b) >> (c))
 
 #define WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(a, b, c) \
     ((WEBRTC_SPL_MUL_16_16(a, b) + ((int32_t) \
                                   (((int32_t)1) << ((c) - 1)))) >> (c))
 
 // C + the 32 most significant bits of A * B
 #define WEBRTC_SPL_SCALEDIFF32(A, B, C) \
@@ skipping 1554 matching lines @@
 // This function multiply a 16-bit word by a 16-bit word, and accumulate this
 // value to a 32-bit integer.
 //
 // Input:
 //      - a    : The value of the first 16-bit word.
 //      - b    : The value of the second 16-bit word.
 //      - c    : The value of an 32-bit integer.
 //
 // Return Value: The value of a * b + c.
 //