Re: RFC: Implementing a new API for value_range

[Aldy Hernandez <aldyh at redhat dot com>]

Sorry, I meant to say it only builds tree-vrp.o.

On Wed, Oct 3, 2018, 09:36 Aldy Hernandez <aldyh@redhat.com> wrote:

> Hi Richard.  Hi folks.
>
> I'd like to implement a clean API that disallows direct access to any of
> the value_range internals.  My aim is a clean API with no change in
> functionality.
>
> This is mostly a clean-up, but could also pave the way for possibly
> changing the underlying implementation in the future so we can unite VPR
> and the on-demand work with a single common code base.
>
> I am quoting the main structure below to give an idea where I'd like to
> head, and am also attaching a proof-of-concept patch to tree-vrp.[hc].
> It is untested and only builds cc1.
>
> Ideally I'd like to evolve this to include other methods that make the
> VRP / vr-values code more readable.
>
> Note: I have added a tree type field (m_type) to make it easy to
> determine the tree type of the range.  Right now a value_range looses
> the range type if UNDEFINED or VARYING, as both min/max are NULL.  If
> there is strong objection to the extra word, we could set min/max to
> integer_zero_node in the type if UNDEFINED/VARYING.  But really, all
> this will be hidden in the API, so we could change the underlying
> representation at will.
>
> Would you be ok with this if I continue down this path?
>
> Thanks.
> Aldy
>
> struct GTY((for_user)) value_range
> {
>    value_range ();
>    value_range (tree type);
>    value_range (tree type, value_range_type, tree, tree, bitmap = NULL);
>    value_range (const value_range &);
>    bool operator== (const value_range &) const;
>    bool operator!= (const value_range &) const;
>    void intersect (const value_range *);
>    void union_ (const value_range *);
>
>    /* Types of value ranges.  */
>    bool undefined_p () const;
>    bool varying_p () const;
>    bool symbolic_p () const;
>    bool numeric_p () const;
>    void set_undefined ();
>    void set_varying ();
>
>    /* Equivalence bitmap methods.  */
>    bitmap equiv () const;
>    void set_equiv (bitmap);
>    void equiv_free ();
>    void equiv_copy (const value_range *);
>    void equiv_clear ();
>    void equiv_and (const value_range *);
>    void equiv_ior (const value_range *);
>
>    /* Misc methods.  */
>    tree type () const;
>    bool null_p () const;
>    bool may_contain_p (tree) const;
>    tree singleton () const;
>    void canonicalize ();
>    void copy_with_equiv_update (const value_range *);
>    void dump () const;
>
>    /* Temporary accessors that should eventually be removed.  */
>    enum value_range_type vrtype () const;
>    tree min () const;
>    tree max () const;
>
>    /* private: These are public because of GTY stupidity.  */
>    enum value_range_type m_vrtype;
>    tree m_min;
>    tree m_max;
>    tree m_type;
>    /* Set of SSA names whose value ranges are equivalent to this one.
>       This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE.  */
>    bitmap m_equiv;
>
>   private:
>    void init (tree type, value_range_type, tree, tree, bitmap);
>    void check ();
> };
>