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Re: RFC: GIMPLE tuples. Design and implementation proposal
- From: Rob1weld at aol dot com
- To: dberlin at dberlin dot org
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 10 Jul 2007 06:31:50 EDT
- Subject: Re: RFC: GIMPLE tuples. Design and implementation proposal
>In a message dated 7/9/2007 2:37:03 P.M. Pacific Daylight Time,
>On 7/9/07, Rob1weld@aol.com <Rob1weld@aol.com> wrote:
>> >In a message dated 7/7/2007 4:04:01 A.M. Pacific Daylight Time, Rob1weld
>> >This page http://deputy.cs.berkeley.edu/ has a link to this document
>> >which describes a means to obtain three-address code here
>> http://hal.cs.berkeley.edu/cil/ext.html#toc24 .
>> >>2007/7/08, Diego Novillo <firstname.lastname@example.org_
>> (mailto:email@example.com) >:
>> >>Any specific reasons why we should? Better memory savings? Faster
>> >>processing? It's not clear from your message what the advantages
>> >>be (ignoring the fact that their implementation language is completely
>You haven't explained what advantages CIL's IR has over GIMPLE.
I thought it was well explained on page:
Please look at this page:
If you choose to run CIL _locally_ (not add it to GCC, but _only_ run it on
then you can program in "Deputy". The Deputy language is very much like "C"
a few additional annotations which allow program checking when it is
Deputy converts it's "C" to 'regular-C' which is processed by GCC. The
result is (obviously)
executable. A simple SED script can remove the annotations and leave you
which can then be released as part of GCC (or you can release 'Deputy-C'
with GCC and
include the SED script which would process the file and produce the source
for stage 1.
Doing that "buys you" a better quality of code tested by CIL (and GCC) which
is more likely
to be correct since it is checked twice. It "costs you" having to learn a
few Deputy annotations.
When you have the CIL source to look at you can read the source and see if
it helps you
with GIMPLE that you are re-writing. You don't need to include CIL with GCC
4.3 (but you
could since you don't need to learn Ocaml to compile it).
The result will be better coding that looks no different and compiles
without any modification
to the current way of building GCC. The second link (above) may help you
> I can't tell, but you may be under the impression GIMPLE is something
> in the future. It is not.
> Our IR is already GIMPLE, and a three address code simplified form of
> C. We are simply talking about changing the underlying datastructures
> that store it.
Yes, I know GCC uses GIMPLE.
>Hint: CIL's IR is almost exactly GIMPLE with alpha renaming over multiple
It is your project to write the way you want. You "RFC letter" said
"Thoughts/comments on the
proposal?". My reply is that this
and this site: _http://www.cs.nyu.edu/leunga/www/MLRISC/Doc/html/INTRO.html_
(http://www.cs.nyu.edu/leunga/www/MLRISC/Doc/html/INTRO.html) provide a
better explanation of IR issues. You might also wish to read
_http://deputy.cs.berkeley.edu/_ (http://deputy.cs.berkeley.edu/) or
this one _http://www.cminusminus.org/_ (http://www.cminusminus.org/) or
Best of luck with your project, I hope it brings a _huge_ advance to GCC.