diff --git a/tools/valgrind-webrtc/memcheck/suppressions.txt b/tools/valgrind-webrtc/memcheck/suppressions.txt
index c9495cbc40..1c02366631 100644
--- a/tools/valgrind-webrtc/memcheck/suppressions.txt
+++ b/tools/valgrind-webrtc/memcheck/suppressions.txt
@@ -612,20 +612,6 @@
    fun:_ZN12_GLOBAL__N_118StatsCollectorTest22TestCertificateReportsERKN3rtc18FakeSSLCertificateERKSt6vectorISsSaISsEES4_S9_
    fun:_ZN12_GLOBAL__N_156StatsCollectorTest_ChainedCertificateReportsCreated_Test8TestBodyEv
 }
-{
-   bug_4143
-   Memcheck:Uninitialized
-   fun:Decode
-   fun:WebRtcIsac_Decode
-   fun:_ZN6webrtc9IsacFloat6DecodeEP16WebRtcISACStructPKhsPsS5_
-   fun:_ZN6webrtc24AudioEncoderDecoderIsacTINS_9IsacFloatEE6DecodeEPKhmPsPNS_12AudioDecoder10SpeechTypeE
-   fun:_ZThn8_N6webrtc24AudioEncoderDecoderIsacTINS_9IsacFloatEE6DecodeEPKhmPsPNS_12AudioDecoder10SpeechTypeE
-   fun:_ZN6webrtc9NetEqImpl10DecodeLoopEPSt4listIPNS_6PacketESaIS3_EEPNS_10OperationsEPNS_12AudioDecoderEPiPNS9_10SpeechTypeE
-   fun:_ZN6webrtc9NetEqImpl6DecodeEPSt4listIPNS_6PacketESaIS3_EEPNS_10OperationsEPiPNS_12AudioDecoder10SpeechTypeE
-   fun:_ZN6webrtc9NetEqImpl16GetAudioInternalEmPsPiS2_
-   fun:_ZN6webrtc9NetEqImpl8GetAudioEmPsPiS2_PNS_15NetEqOutputTypeE
-   fun:_ZN6webrtc35NetEqDecodingTest_DecoderError_Test8TestBodyEv
-}
 {
    bug_4147_1
    Memcheck:Unaddressable
diff --git a/webrtc/modules/audio_coding/codecs/isac/main/source/isac.c b/webrtc/modules/audio_coding/codecs/isac/main/source/isac.c
index d2260e26bb..db78e6de2e 100644
--- a/webrtc/modules/audio_coding/codecs/isac/main/source/isac.c
+++ b/webrtc/modules/audio_coding/codecs/isac/main/source/isac.c
@@ -1096,6 +1096,13 @@ static int16_t Decode(ISACStruct* ISAC_main_inst,
   memcpy(instISAC->instLB.ISACdecLB_obj.bitstr_obj.stream, encoded,
          lenEncodedLBBytes);
 
+  /* We need to initialize numSamplesLB to something; otherwise, in the test
+     for whether we should return -1 below, the compiler might generate code
+     that fools Memcheck (Valgrind) into thinking that the control flow depends
+     on the uninitialized value in numSamplesLB (since WebRtcIsac_DecodeLb will
+     not fill it in if it fails and returns -1). */
+  numSamplesLB = 0;
+
   /* Regardless of that the current codec is setup to work in
    * wideband or super-wideband, the decoding of the lower-band
    * has to be performed. */