PVS-Studio warning V595 for Newton Game Dynamics

void dgRedBackNode::RemoveFixup (....)
{
  ....
  tmp = ptr->m_right;
  if (!ptr || !tmp) {
    return;
  ....
}

This suspicious code was found in Newton Game Dynamics project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'ptr' pointer was utilized before it was verified against nullptr. Check lines: 229, 230. dgtree.cpp 229

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/