Re: 'SR.1419' is used uninitialized in this function...

[Benjamin Redelings <bredelin at ucla dot edu>]

Gabriel Dos Reis wrote:

> Andrew Pinski <pinskia@physics.uc.edu> writes:
>
> | On Jan 25, 2005, at 12:58 PM, Benjamin Redelings wrote:
> | 
> | > Hello,
> | >
> | >    I'm testing 4.0 snapshot 2005-01-15 by trying to compile my
> | > program.  I get error messages like the following a few times:
> | >
> | >    'SR.1419' is used uninitialized in this function...
> | >
> | > I'm guessing that this is an SSA name and should not be reported to
> | > the user.  Is this a known bug?  Should I file a PR?
> | 
> | Yes it is known but it is most likely a bug in your code.
> | The problem is that SR.1419 should really be named
> | "<<unnamed>>.structmember".
>
> Not really.  I've already filled a PR (which I think  you quickly
> closed) where SR.xxxx should have been A::i (where A is a base
> class).  I wanted to fix this by using DECL_ABSTRACT_ORIGIN but RTH
> thinks that is not appropriate.  Anyhow, we need to put a back
> reference to the original tree that was SRAed.
>
> -- Gaby
>  

I now have a 30-line test-case (attatched) which triggers two bugs:
a) the structure member has a name, but is not named.
b) the structure member is not actually used, despite the warning.

Ways to make the problem go away include:
a) make a function non-virtual
b) make a function not a template
c) remove the undefined, and supposedly unused variable.
d) turn off all optimization.

-BenRI
struct branchview;

struct iterator 
{
  unsigned circuits;  // Warning goes away if you remove this line

  virtual branchview operator*() const;  // Warning goes away if you remove 'virtual'

  iterator() {}
};

struct branchview 
{
  iterator my_iterator() const {return iterator();}

  branchview(){}
};

inline branchview iterator::operator*() const {
  return branchview();
}

// You have to do this inside a template to get the bug, I think.
template<class iterator_t>
inline void append(const iterator_t& start, branchview& t) {
  iterator_t i = start;
  t = *i;
}

void iterator_set(const branchview& bv1,branchview& bv2) {
  append(bv1.my_iterator(),bv2);
}