Re: Avoid generating useless range info

[Richard Biener <richard.guenther@gmail.com>]

On Fri, Jun 23, 2017 at 12:32 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Fri, Jun 23, 2017 at 12:24:25PM +0200, Richard Biener wrote:
>> > void
>> > set_nonzero_bits (tree name, const wide_int_ref &mask)
>> > {
>> >   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
>> >   if (SSA_NAME_RANGE_INFO (name) == NULL)
>> >     set_range_info (name, VR_RANGE,
>> >    TYPE_MIN_VALUE (TREE_TYPE (name)),
>> >    TYPE_MAX_VALUE (TREE_TYPE (name)));
>> >   range_info_def *ri = SSA_NAME_RANGE_INFO (name);
>> >   ri->set_nonzero_bits (mask);
>> > }
>> >
>> > Let me know how you'd like me to proceed.
>>
>> Just factor out a set_range_info_raw and call that then from here.
>
> And don't call it if the mask is all ones.  Perhaps set_range_info
> and set_nonzero_bits even should ggc_free and clear earlier range_info_def
> if the range is all values and nonzero bit mask is all ones.
> Or do we share range_info_def between multiple SSA_NAMEs?  If yes, of course
> we shouldn't use ggc_free.

We shouldn't as we don't copy on change.  We do for points-to but only for the
bitmap pointer IIRC.

Richard,

>
>         Jakub