Re: [PATCH] Pass correct type to irange::contains_p() in ipa-cp.cc.

[Aldy Hernandez <aldyh@redhat.com>]

On 4/24/23 14:10, Richard Biener wrote:
> On Mon, Apr 24, 2023 at 1:51 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>>
>>
>>
>> On 4/24/23 10:30, Richard Biener wrote:
>>> On Mon, Apr 24, 2023 at 9:44 AM Aldy Hernandez via Gcc-patches
>>> <gcc-patches@gcc.gnu.org> wrote:
>>>>
>>>> There is a call to contains_p() in ipa-cp.cc which passes incompatible
>>>> types.  This currently works because deep in the call chain, the legacy
>>>> code uses tree_int_cst_lt which performs the operation with
>>>> widest_int.  With the upcoming removal of legacy, contains_p() will be
>>>> stricter.
>>>>
>>>> OK pending tests?
>>>>
>>>> gcc/ChangeLog:
>>>>
>>>>           * ipa-cp.cc (ipa_range_contains_p): New.
>>>>           (decide_whether_version_node): Use it.
>>>> ---
>>>>    gcc/ipa-cp.cc | 16 +++++++++++++++-
>>>>    1 file changed, 15 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/gcc/ipa-cp.cc b/gcc/ipa-cp.cc
>>>> index b3e0f62e400..c8013563796 100644
>>>> --- a/gcc/ipa-cp.cc
>>>> +++ b/gcc/ipa-cp.cc
>>>> @@ -6180,6 +6180,19 @@ decide_about_value (struct cgraph_node *node, int index, HOST_WIDE_INT offset,
>>>>      return true;
>>>>    }
>>>>
>>>> +/* Like irange::contains_p(), but convert VAL to the range of R if
>>>> +   necessary.  */
>>>> +
>>>> +static inline bool
>>>> +ipa_range_contains_p (const irange &r, tree val)
>>>> +{
>>>> +  if (r.undefined_p ())
>>>> +    return false;
>>>> +
>>>> +  val = fold_convert (r.type (), val);
>>>
>>> I think that's wrong, it might truncate 'val'.  I think we'd want
>>>
>>>      if (r.undefined_p () || !int_fits_type_p (val, r.type ()))
>>>        return false;
>>
>> This won't work for pointers.  Is there a suitable version that handles
>> pointers as well?
> 
> Where does it not work?  And when do you get pointer values/types
> where they mismatch sufficiently (how?) to make ranger unhappy?
> 

It's not ranger that's unhappy, this is just irange::contains_p().

IPA works on both integers and pointers, and pointers don't have 
TYPE_MIN/MAX_VALUE defined, so we ICE in int_fits_type_p:

   type_low_bound = TYPE_MIN_VALUE (type);
   type_high_bound = TYPE_MAX_VALUE (type);