Re: open64 versus gcc

Gary Oblock <mwso@earthlink.net>
3 Dec 2006 21:34:35 -0500

          From comp.compilers

Related articles
[7 earlier articles]
Re: open64 versus gcc alewando@fala2005.com (A.L.) (2006-12-01)
Re: open64 versus gcc alewando@fala2005.com (A.L.) (2006-12-01)
Re: open64 versus gcc jthorn@aei.mpg-zebra.de (Jonathan Thornburg -- remove -animal to reply) (2006-12-03)
Re: open64 versus gcc dnovillo@redhat.com (Diego Novillo) (2006-12-03)
Re: open64 versus gcc lindahl@pbm.com (Greg Lindahl) (2006-12-03)
Re: open64 versus gcc bmoses-nospam@cits1.stanford.edu (Brooks Moses) (2006-12-03)
Re: open64 versus gcc mwso@earthlink.net (Gary Oblock) (2006-12-03)
Re: open64 versus gcc Sid-Touati@inria.fr (ST) (2006-12-06)
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From: Gary Oblock <mwso@earthlink.net>
Newsgroups: comp.compilers
Date: 3 Dec 2006 21:34:35 -0500
Organization: EarthLink Inc. -- http://www.EarthLink.net
References: 06-11-09406-11-100 06-11-104 06-11-113 06-11-120 06-11-124
Keywords: GCC, arithmetic

Diego Novillo wrote:


> dz wrote on 11/29/06 00:52:
>> The criteria I am looking for is stability and the strength of some
>> basic analysis in the compiler such as alias analysis. Can anyone
>> comment on that ?
>
> For alias analysis, GCC uses a fairly sophisticated constraint-based
> points-to analysis and complements it with type-based disambiguation.
> You can read about it in the various GCC Summit proceedings over the
> last 2-3 years. You can find them in http://gcc.gnu.org/wiki
>
> I'm not sure what exactly you mean by "some basic analysis", but you
> will find GCC a fairly featureful compiler. In terms of strength, GCC
> is the system compiler of every Linux distribution out there, so it is
> thoroughly tested and breaking it takes a bit of effort.


I was worked on a custom VLIW scheduler grafted into gcc 4.x and at the
RTL level the alias information available wasn't all that great in my
opinion. I think there is a fundementail lack of communication between
the tree level and the RTL levels because though the initial RTL
generated has a way to get at the tree level information the subsequent
optimizations need to preserve it (which they don't.)


-- Gary


--
Bronze Dreams
http://www.bronzedreams.com



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