refinements to definition of TREE_READONLY ?

[Olivier Hainque]

Richard Guenther wrote:
> >   Don't set TREE_RO on the decl if !TREE_STATIC, in gigi (we might
> >   decide it doesn't make sense and document accordingly).
> 
> That would work.

 Both doing the thing in gigi and deciding that TREE_RO only makes
 sense if TREE_STATIC as well ?

 (I have no strong feeling about it, just asking to make sure I'm
 getting what you meant) 
 
> >   Clear TREE_RO in gimplify_decl_expr. We could leave
> >   DECL_INITIAL there in this case as well.
> 
> This as well.

 OK.

> >  Sorry, this part was confused on my side: the issue we had with
> >  sra was with a static rhs (global Ada constant integer), of value 1,
> >  marked TREE_RO and without DECL_INITIAL.
> 
> So what happened?

 The lhs was initialized with 0 instead of 1.
 
> The code in tree-sra looking at DECL_INITIAL looks fine.

 If it's ok to assume !DECL_INITIAL is equivalent to 0, indeed.

 Is it really ?