> @@ -266,6 +267,38 @@ private:
> bool meet_with_1 (unsigned new_align, unsigned new_misalign);
> };
>
> +/* Lattice of known bits, only capable of holding one value.
> + Similar to ccp_lattice_t, mask represents which bits of value are
> constant.
> + If a bit in mask is set to 0, then the corresponding bit in
> + value is known to be constant. */
> +
> +class ipcp_bits_lattice
> +{
> +public:
> + bool bottom_p () { return m_lattice_val == IPA_BITS_VARYING; }
> + bool top_p () { return m_lattice_val == IPA_BITS_UNDEFINED; }
> + bool constant_p () { return m_lattice_val == IPA_BITS_CONSTANT; }
> + bool set_to_bottom ();
> + bool set_to_constant (widest_int, widest_int);
> +
> + widest_int get_value () { return m_value; }
> + widest_int get_mask () { return m_mask; }
> +
> + bool meet_with (ipcp_bits_lattice& other, unsigned, signop,
> + enum tree_code, tree);
> +
> + bool meet_with (widest_int, widest_int, unsigned);
> +
> + void print (FILE *);
> +
> +private:
> + enum { IPA_BITS_UNDEFINED, IPA_BITS_CONSTANT, IPA_BITS_VARYING }
> m_lattice_val;
> + widest_int m_value, m_mask;
Please add comment for these, like one in tree-ssa-ccp and mention they are the
same
values.
> +
> + /* For K&R C programs, ipa_get_type() could return NULL_TREE.
> + Avoid the transform for these cases. */
> + if (!parm_type)
> + return dest_lattice->set_to_bottom ();
Please add TDF_DETAILS dump for this so we notice if we drop useful info for no
good reasons. It also happens for variadic functions but hopefully not much
more.
The patch is OK with those changes.
thanks,
Honza
