Re: [PATCH, 2/2] Handle recursive restrict in function parameter

[Richard Biener <rguenther at suse dot de>]

On Tue, 3 Nov 2015, Tom de Vries wrote:

> On 01/11/15 19:20, Tom de Vries wrote:
> > On 01/11/15 19:03, Tom de Vries wrote:
> > > So, the new patch series is:
> > > 
> > >       1    Rename make_restrict_var_constraints to make_param_constraints
> > >       2    Handle recursive restrict in function parameter
> > > 
> > > I'll repost in reply to this message.
> > > 
> > 
> > This patch adds handling of all the restrict qualifiers in the type of a
> > function parameter.
> > 
> 
> And reposting an updated version, now that the toplevel parameter in
> make_param_constraints has been eliminated.

@@ -5195,6 +5197,8 @@ struct fieldoff
   unsigned may_have_pointers : 1;

   unsigned only_restrict_pointers : 1;
+
+  varinfo_t restrict_var;
 };

store the varinfo ID here, 'unsigned int restrict_var' which ends
up not changing fieldoff size.  get_varinfo (restrict_var) will get
you the varinfo_t.

@@ -5374,6 +5380,19 @@ push_fields_onto_fieldstack (tree type, 
vec<fieldoff_s> *fieldstack,
                  = (!has_unknown_size
                     && POINTER_TYPE_P (field_type)
                     && TYPE_RESTRICT (field_type));
+               if (handle_param
+                   && e.only_restrict_pointers
+                   && !type_contains_placeholder_p (TREE_TYPE 
(field_type)))
+                 {
+                   varinfo_t rvi;
+                   tree heapvar = build_fake_var_decl (TREE_TYPE 
(field_type));
+                   DECL_EXTERNAL (heapvar) = 1;
+                   rvi = create_variable_info_for_1 (heapvar, 
"PARM_NOALIAS",
+                                                     true, true);
+                   rvi->is_restrict_var = 1;
+                   insert_vi_for_tree (heapvar, rvi);
+                   e.restrict_var = rvi;
+                 }

hmm, can you delay this to the point we actually will use field-sensitive
stuff?  That is, until create_variable_info_for_1 decided to use a
multi-field variable?  Say, here:

+      if (handle_param
+         && newvi->only_restrict_pointers
+         && fo->restrict_var != NULL)
+       {
+         make_constraint_from (newvi, fo->restrict_var->id);
+         make_param_constraints (fo->restrict_var);
+       }

?  Looks like then you don't need the new field at all.

Thanks,
Richard.