Volatile / TREE_THIS_VOLATILE question

[Tobias Burnus]

Hi,

if I dump the tree of the following C program,
   int main() { volatile int i; i = 5; return 0; }
I get (-tree-original):
{
  volatile int i;
    volatile int i;
  i = 5;
  return 0;
}

However, if I apply my volatile-in-Fortran patch [1] and compile
  integer, volatile :: i; i = 5; end
then the dumped tree contains:
{
  int4 i;
  _gfortran_set_std (70, 127, 0);
  i = 5;
}

I use in my patch:
+ if (sym->attr.volatile_)
+   TREE_THIS_VOLATILE (decl) = 1;

Question:
- Is TREE_THIS_VOLATILE the right thing to do?
- How do I see (tree dump etc.) whether I did the right change?

Tobias

PS: I sneaked at g95 and there Andy also uses TREE_THIS_VOLATILE; g95
-fdump-tree-original has also no "volatile".

[1] http://gcc.gnu.org/ml/gcc-patches/2006-10/msg01601.html