[Bug rtl-optimization/39081] missed optimization: un-needed copy of structure.

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2009-02-06 01:35 -------
>   tv = my_tv_maker(434.23);  // over-write previous tv.

This needs to have a space for the return value as tv can be accessed via
my_tv_maker as the address of it was passed to an extern function.

Think of:

extern TV *a1;
TV my_tv_maker(float tr)
{
  TV myTV;
  myTV. confidence = tr;
  use (a1-> confidence);
  return myTV;
}
 void other(TV *a)
{
a1 = a;
}

So this bug is invalid as tv in my_subr can be exported for use in my_tv_maker.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39081