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Re: [tree-ssa] Any good sources of documentation?
- From: "Marty Hauff" <marty dot hauff at rmit dot edu dot au>
- To: <dnovillo at redhat dot com>
- Cc: <gcc at gcc dot gnu dot org>
- Date: Tue, 20 May 2003 16:12:04 +1000
- Subject: Re: [tree-ssa] Any good sources of documentation?
Thanks for your response. There was an query posted by Matthieu Moy on 5/4 regarding "Where can I get the output of the front-end". In this query he asked if there was a moment in the compilation at which we can see the whole program in one single tree? The response suggested trying cgraph_finalize_compilation_unit (). From your response I am assuming that tree-ssa does not parse the _whole_ program into one huge tree but rather parses each function individually. I understand that this strategy uses far less memory but could tree-ssa be modified to parse the whole program into a single tree and if so would it break it?
Specifically I am trying to use the compiler to give me information about what hardware resources would be most useful for a given application. I can't use the mainline code because it converts to RTL (which is machine dependent) very early on and does most of its optimisations in the RTL. Ideally I would like to receive an already optimised tree that can be analysed to deduce an ideal hardware architecture. Do you think that tree-ssa is the tool for this?????
Oh and by the way, I will be attempting to walk on water shortly after accomplishing all this.....
>>> Diego Novillo <email@example.com> 19/05/03 23:23:14 >>>
On Mon, 2003-05-19 at 04:22, Marty Hauff wrote:
> I'm trying to find out how the tree-ssa branch performs its
> compilation and optimisation. I've found the doxygen stuff on the web
> but I need something a bit higher level at this stage.
Most documentation is in the source code itself. There is a high-level
description of the optimization process in the project page
(http://gcc.gnu.org/projects/tree-ssa/). After the GCC summit next
week, I will post the tree SSA paper and slides in my home page.
> Specifically I am looking to find a point during compilation where the
> most optimisation has been done PRIOR to target specific processing
> having been started.
> The main gcc branch is no good to me because it only does things on
> a function by function basis. According to the docs, tree-ssa
> processes the whole source _before_ generating rtl etc. (or have I got
> this wrong?)
Both mainline and tree-ssa operate in the same way. If you use
-funit-at-a-time, then compilation proceeds in call graph order.