Is this reordering valid?

In "C++ and the Perils of Double-Checked Locking", Scott Meyers and
Andrei Alexandrescu brought up a good point on how it is impossible to
avoid the reorder problem.
But I think there might be something that I would disagree. Look at the
code below:

C* pc = new C();

It involves three steps:

1. allocation of raw memory
2. construction of C
3. assignment

The question is, is it really allowed by the standard that 2 and 3
could be reordered?
Before you start to judge, let me show you this little chunk of code:

struct C{
  C()
  {
    throw std::runtime_exception("...");
  }
};

C* pc = 0;
int main(){
try{
pc = new C();
}
catch(...)
{
if(pc) some_library_IO_func(); // observable behavior
}
}

Here, whether step 2 and step 3 are reordered have an definite effect
on the observable behavior.
So, are they still allowed to be reordered?

If this isn't enough, how about qualifying pc with volatile?

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