Re: Screaming-Fist: a JIT framework for Guile

[Nala Ginrut]

Hi folks, I confirmed that gcc_jit_context_new_rvalue_from_int is an
abstract for various numbers.

So the number's validation would be added then.

Best regards.

On Tue, Dec 5, 2023, 18:14 Nala Ginrut <nalaginrut@gmail.com> wrote:

> Hi Maxime!
>
>
>
> On Tue, Dec 5, 2023, 05:26 Maxime Devos <maximedevos@telenet.be> wrote:
>
>>
>>
>> Op 03-12-2023 om 18:26 schreef Nala Ginrut:
>> > (jit-define (square x)
>> >    (:anno: (int) -> int)
>> >    (* x x))
>> > (square 5)
>>
>>
>> Potentially-overflowing arithmetic involving ints (not unsigned ints,
>> but ints)? Best document somewhere to what the jit code '(* x x)'
>> evaluates when (not (<= min-int (* x x) max-int))).
>>
>
> There's no type inference in libgccjit, so the high level framework has to
> handle accurate types.
>
> I use "int" here because libgccjit only provides int rvalue constructor,
> yet. It seems lack of rich number types as rvalue in the present
> implementation. Even boolean has to be handled by high level framework and
> cast it to int respectively.
>
> May be we need GCC folks help.
>
>
>> Personally, I'm in favor of explicit long names like
>>
>> */error-on-overflow     (<-- maybe on the C-level the function could
>> return a tagged union representing (failure [no value]) / (success [some
>> value], at a slight performance cost)
>> */wrap-around
>> */undefined-on-overflow (<-- like in C, for maximal performance and
>> dragons).
>>
>
> There was such check, but I've removed it. Since even you detect the
> int/short/long exactly, libgccjit only provides int rvalue for all cases of
> numbers. I'm not sure if it's waiting for contribution or intended as an
> unified int abstract.
>
>
>> (Likewise for +, - and unsigned int)
>>
>> Sure, they are a bit verbose, but they are explicit and
>> non-explicitness+undefined behaviour of'*' in C has caused serious
>> issues in the past, so I'd think it's better that the programmer has to
>> choose what, in their situation, are the appropriate semantics.
>>
>
> I see your point :-)
> Yes, it's a bit hard to provide an abstract arithmetic with type inference
> for all cases, providing each for different types will be easier and
> flexible.
>
> Thanks!
> Best regards.
>
>
>>