PVS-Studio warning V567 for IPP Samples

void VC1BRC_I::CompleteFrame(ePType picType)
{
  ...
  m_Quant.LimIQuant = m_Quant.LimIQuant--;
  ...
  m_Quant.IQuant = m_Quant.IQuant--;
  ...
}

This suspicious code was found in IPP Samples project by PVS-Studio static code analyzer.
Warning message is:
V567 Undefined behavior. The 'm_Quant.LimIQuant' variable is modified while being used twice between sequence points. vc1_enc umc_vc1_enc_brc_gop.cpp 241

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/