Re: [PATCH 1/2]middle-end: Fix wrong overmatching of div-bitmask by using new optabs [PR108583]

[Andrew MacLeod <amacleod@redhat.com>]

On 2/15/23 13:42, Andrew MacLeod wrote:
>
> On 2/15/23 12:50, Andrew MacLeod wrote:
>>
>> On 2/15/23 12:13, Tamar Christina wrote:
>>>> On 2/15/23 07:51, Tamar Christina wrote:
>> void
>> operator_plus::wi_fold (irange &r, tree type,
>>                         const wide_int &lh_lb, const wide_int &lh_ub,
>>                         const wide_int &rh_lb, const wide_int &rh_ub) 
>> const
>> {
>>   wi::overflow_type ov_lb, ov_ub;
>>   signop s = TYPE_SIGN (type);
>>
>>   // Do whatever wideint magic is required to do this adds in higher 
>> precision
>>   wide_int new_lb = wi::add (lh_lb, rh_lb, s, &ov_lb);
>>   wide_int new_ub = wi::add (lh_ub, rh_ub, s, &ov_ub);
>>
>>   r = int_range<2> (type, new_lb, new_ub);
>> }
>>
>>
>> The operator needs to be registered, I've attached the skeleton for 
>> it.  you should just have to finish implementing wi_fold().
>>
>> in theory :-)
>>
> You also mentioned earlier that some were tree codes, some were 
> internal function calls?  We have some initial support for built in 
> functions, but I am not familiar with all the various forms they can 
> take.  We currently support CFN_ functions in
>
>   gimple-range-op.cc, gimple_range_op_handler::maybe_builtin_call ()
>
> Basically this is part of a "gimple_range_op_handler"  wrapper for 
> range-ops which can provide a range-ops class for stmts that don't map 
> to a binary or unary form.. such as built in functions.
>
> If you get to the point where you need this for a builtin function, I 
> can help you through that too.  Although someone may have to also help 
> me through what differentiates the different kinds of internal 
> function :-)    I presume they are all similar in some way.
>
> Andrew
>
Oh yeah, and in case you haven't figured it out on your own, you'll have 
to remove WIDEN_MULT_EXPR from the range-ops init table.   This 
non-standard mechanism only gets checked if there is no standard 
range-op table entry for the tree code :-P

Andrew

Andrew