Re: [Tinycc-devel] Thumb2 codegen ready for review

[Michael Matz]

Hello,


On Mon, 25 May 2020, Erlend Sveen wrote:

> Yeah, it is probably best to drop that test unless there is a way to 
> make a smaller version of it that would still be useful, if the test 
> makes sense from a codegen perspective at all. Maybe if it is fine as 
> long as it passes for x86 or something.

I did find a (real) problem in one of my riscv64 patches with this test 
caused by too large functions, so it was helpful.  The general 
functionality it wants to test (cleanups for local variables) can also be 
had with a limited variant, so you could play with target macros to enable 
only (say) INCR_GI2 or GI3 on small targets.  (i.e. as long as it's still 
the large one for hosted/native targets ...)


Ciao,
Michael.
> Strange that you got different results with the print function, I was
> so certain I did not have that issue but maybe I remember it wrong.
> It could also be due to platform differences, looks like you tested
> with Windows while I'm running Linux.
>
> I do of course hope to get it into the main repository but I also think
> it needs some more fixing first. Hopefully more people get to have a
> look at it over the next few weeks for some feedback.
>
> Regards,
> Erlend S
>
> ____________________________________________________________________________
> Fra: Tinycc-devel <tinycc-devel-bounces+erlend.sveen=address@hidden>
> på vegne av grischka <address@hidden>
> Sendt: mandag 25. mai 2020 14:03
> Til: address@hidden <address@hidden>
> Emne: Re: [Tinycc-devel] Thumb2 codegen ready for review  
> Erlend Sveen wrote:
> >> * 117_cleanup_nofloat.c : INCR_GI7 is really slow and probably wouldn't
> >>   find bugs that INCR_GI3 for example would not.
> > I don't understand what you mean here. Note that I just copied the integer
> parts of test 101
> > here, and could not get this test to work anyways since it generates a 7MB
> file before running
> > into some limits with branching, and my microcontroller does not have
> enough memory to run
> > it either. This is actually the only test that totally fails (see
> spreadsheet I wrote about).
>
> Ok, so I note that it's not only really slow but also really big, and
> that this mis-feature already does exist in our repository.
>
> Anyway, I don't think we really want stripped down copies of already
> existing tests.  The original tests may work at some point or they can
> be excluded for that platform or the original version might be adjusted
> if it doesn't defeat its purpose.
>
> > print_double is not meant to be accurate at all. All that matters is that
> > GCC and TCC produces the same number.
>
> That was the point.  They don't. (not with a i386-mingw-gcc).
>
> >> You might want to add some notes somewhere though, about how people can
> >> build this and how and where they can use it at all. ;)
> > Absolutely, but where? tcc-doc.texi? The most important thing to document
> is probably the
> > limitations (that I hope to solve). But for what I use it for, it kinda
> "just works" when used as
> > a regular cross compiler 🙂 . Actually running TCC itself on the MCU is
> much more complicated
> > of course, which is why I made that extra repo.
>
> Ok, I looked at your scripts at
>    https://git.erlendjs.no/erlends-os/usr/compiler/tree/master/tinycc
> which of course have all the information I could think of.
>
> Well, so at this point I'd maybe suggest just to put the web-link to
> this into the comment header of your arm-thumb generator.
>
> I think the decision you need to make is when you want to switch from
> your clone to the tinycc main repository as THE PLACE where you make
> your work on the tinycc core visible to the public audience.  Sooner
> or later, both has advantages and disadvantages.
>
> --- grischka
>
> > Regards,
> > Erlend S.
> >
>
>
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