PVS-Studio warning V526 for PostgreSQL

Datum
pg_stat_get_activity(PG_FUNCTION_ARGS)
{
  ....
  if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
             sizeof(zero_clientaddr) == 0))
  ....
}

This suspicious code was found in PostgreSQL project by PVS-Studio static code analyzer.
Warning message is:
V526 The 'memcmp' function returns 0 if corresponding buffers are equal. Consider examining the condition for mistakes. postgres pgstatfuncs.c 712

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/