How to clean up i386 machine description?

[Colin Douglas Howell <howell at cs dot stanford dot edu>]

Jeffrey A Law writes:
> 
>   > How about brand-new gcc hackers?  :-)
> Well, for them I'd try to find a slightly smaller project(s) to start getting
> a handle on how gcc itself works.
> 
> Many of us got started by either implementing some missing feature or
> optimization we needed, or by fixing bugs that were important to us or
> our employers.
> 
>   > works, it is clearly a huge, complex beast.  How would you suggest I
>   > proceed?
> It is certainly a huge complex beast.  How to proceed?  Find a particular
> optimization or problem you're interested in.  Maybe try to work with someone
> like Jan Hubicka that is working on x86 backend specific improvements (and
> there's lots of opportunity there).

I've been spending the last several weeks reading the gcc internals
manual and browsing through the code to get more of a handle on how
the EGCS back end works.  At this point I think I have a pretty good
general grasp of it, although of course there are many details I am
still ignorant of.

I'm really concerned with the x86 back end right now, and I've been
reading Jan Hubicka's messages to the EGCS mailing lists.  I've also
been looking at the x86 machine description itself.  It looks ugly, to
say the least, and needs a lot of cleaning up.  As you said in a
thread started by one of Jan's messages, many insns are output as a
series of machine instructions; this must be fixed in order to
schedule instructions effectively.

I've just scratched the surface of the x86 machine description; I
still have a lot to read.  Besides the problem of single insns being
output as multiple instructions, do you have any ideas on how best to
go about fixing the description?  What would you say needs to be done
first?

Also, I'm wondering about Jan's patches.  None of them seem to have
gone into the CVS tree yet.  Is there a holdup on the copyright
assignment form, or some other problem?

Speaking of that form, I'm going to have to submit one myself if I'm
going to do any real work on EGCS.  I currently work for Stanford
University; does anyone know if there are other issues which must be
settled to prevent Stanford trying to lay claim to any work I do?
(Not that Stanford is really bad on this score, but this should be
cleared up.)

-- 
Colin Douglas Howell                    Systems Administrator
e-mail:  howell@cs.stanford.edu         Computer Facilities Group
office:  (650) 723-2491                 Computer Science Department
                                        Stanford University