In C++11 and later, is it still optimal to do an "empty" check before a "range for"?

I'm currently updating some older C++ code that I have that iterates over STL container types, and I'm finding a lot of code like this:

if (!edgeSet.empty())
{
  for(typename EdgeSet::const_iterator iter = edgeSet.begin(); iter != edgeSet.end(); iter++)
  {
    ...
  }
}

Which I am turning (successfully) into the equivalent:

if (!edgeSet.empty())
{
  for(auto& edge : edgeSet)
  {
    ...
  }
}

And I was wondering... is the "empty" check necessary for a "range for"? I would imagine it would be necessary in the older "iterator style" for loop to avoid a useless initialization and comparison / branch, but I'm curious if a "range for" automatically does an empty check or not before it even starts.

Further, if the optimization does happen, does it happen at all optimization levels (including no optimization: -O0 )?

Thanks in advance.