[LLVMdev] Bignum development

[Eli Friedman]

On Fri, Jun 11, 2010 at 5:41 PM, Bill Hart <goodwillhart at googlemail.com> wrote:
> What is i1? Sorry for the really daft question. These short
> abbreviations are sometimes hard to look up.....

1-bit integer; in practice, usually used like a boolean, although it
supports the full complement of integer operations.

>> There have really only been sporadic queries about practical support
>> for real multi-precision arithmetic, but we'd welcome any
>> improvements.
>
> Sure. I'm mainly thinking of LLVM's stated aim of "offering support
> for other non-C languages", which is (a paraphrase of) what you have
> somewhere, listed in the open projects on the LLVM site. It occurs to
> me that bignum support is one thing that many languages require, but
> currently have to use GMP for. If your language is BSD licensed
> though, that is out of the question, hence some pretty poor bignum
> implementations out there (I mean relatively speaking
> performance-wise).
>
> There are obviously numerous ways we might use LLVM to aid development
> of "bsdnt". I'll keep exploring those options. It sounds like, for the
> time being, analysing existing code output and looking for ways to
> improve it on certain arches is perhaps one way we may be of
> assistance.

Sounds like an interesting project.  We're always happy to answer
questions and add projects to the http://llvm.org/ProjectsWithLLVM/
page.

> By the way, the LLVM website is absolutely spectacular. The attention
> to detail is amazing. There were some things that I found oddly
> difficult to find, and I am still mystified why I googled for such a
> long time for something like LLVM (days of googling, not minutes) and
> didn't hit upon it. I wonder if I simply overlooked it because I
> thought it was "just" a JIT or virtual machine.
>
> Heh, ever thought of putting lots of terms like, "faster than C",
> "high level assembly language", "lower level than C", "modern compiler
> back end", "better than gcc's RTL", "similar to RTL", etc. on the
> site, to make things more visible to a certain class of google
> searches. (Better than gcc, faster than gcc, BSD licensed C compiler,
> beats gcc in the programming language shootout - heh, naughty me). :-)

I believe Chris wrote most of the copy on the homepage; perhaps he can comment.

-Eli