PVS-Studio warning V597 for Asterisk

static int silence_generator_generate(....)
{
  short buf[samples];

  struct ast_frame frame = {
    .frametype = AST_FRAME_VOICE,
    .data.ptr = buf,
    .samples = samples,
    .datalen = sizeof(buf),
  };
  frame.subclass.format = ast_format_slin;

  memset(buf, 0, sizeof(buf));      //<==
  ....
}

This suspicious code was found in Asterisk project by PVS-Studio static code analyzer.
Warning message is:
V597 The compiler could delete the 'memset' function call, which is used to flush 'buf' buffer. The RtlSecureZeroMemory() function should be used to erase the private data. channel.c 7742

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