[Bug tree-optimization/107561] [13 Regression] g++.dg/pr71488.C and [g++.dg/warn/Warray-bounds-16.C -m32] regression due to -Wstringop-overflow problem

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107561

--- Comment #21 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #19)
> And on
> void bar (void);
> struct X {
>   X (int);
>   int i;
>   int j;
>   void baz (int);
> };
> 
> X::X(int k)
> {
>   i = k;
>   bar ();
>   j = i != k;
> }
> 
> void
> X::baz(int k)
> {
>   i = k;
>   bar ();
>   j = i != k;
> }
> while I see
>   # PT = { D.2822 } (nonlocal, restrict)
>   struct X * const this_5(D) = this;
> later on in the dumps (not really sure what exactly causes it), in baz it is
> not there:
>   # PT = nonlocal
>   struct X * const this_5(D) = this;

We have

static void
intra_create_variable_infos (struct function *fn)
{     
  tree t;
  bitmap handled_struct_type = NULL;
  bool this_parm_in_ctor = DECL_CXX_CONSTRUCTOR_P (fn->decl);
...
      varinfo_t p           
        = create_variable_info_for_1 (t, alias_get_name (t), false, true,
                                      handled_struct_type, this_parm_in_ctor);

and 'this_parm_in_ctor' makes the pointer as if it were restrict qualified.
Not sure why we chose that route as compared to actually making it restrict
(I think we did that at some point but it caused issues?).

As said the real issue is that I didn't implement effects of restrict
qualification on calls.  I'll see to give it a try for next stage1.