Re: [PATCH] src/comp.c: Use constructor expressions when possible.

[Andrea Corallo]

Vibhav Pant <vibhavp@gmail.com> writes:

> On Sat, 2022-10-15 at 15:59 +0000, Andrea Corallo wrote:
>> 
>> Hi Vibhav,
>> 
>> could you please produce the same without your patch an report it here?
>> Also, do you see any difference in geenrated asm code?
>> 
>
> Hi Andrea,
>
> I've attached the code generated generated with the current codebase below,
> alongside the source-accompanied disassembly of both versions of the compiler.
> The main difference that I noticed is the lack of `Lisp_Object` variables
> emitted by `emit_coerce` in the new file. As far as the generated assembly 
> goes,
> luckily, there doesn't seem to be any difference between the two yet, as gcc 
> is
> optimizing those variables away.
>
> Thanks,
> Vibhav

Thanks,

to be honest I'm not very ecstatic about this patch.  It adds purely
cosmetic changes to the libgccjit IR we generate at the price of more
ifdef kludge in our back-end.  The fact that we have to allocate anyway
the temporary array in the stack to pass it by reference to funcall,
makes the code not further optimizable.

I should convince myself the trade-off for this patch is beneficial but
ATM I don't manage to.

  Andrea