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Re: [tree-ssa-branch] Can I utilize the CFG?
- From: Diego Novillo <dnovillo at acm dot org>
- To: zhongda lu <ludaxd at yahoo dot com dot cn>
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 6 Oct 2002 10:29:41 -0400
- Subject: Re: [tree-ssa-branch] Can I utilize the CFG?
- References: <20021006075115.53840.qmail@web15107.mail.bjs.yahoo.com>
On Sun, 06 Oct 2002, zhongda lu wrote:
> Maybe this is not hopeful for me,because I would like the
> original AST being transformed to CFG.How could I control your
> code to achieve this? Another
>
You can't. The CFG is built after simplification. If you feed
it an unsimplified program it will either build the wrong CFG or
abort. The flowgraph builder is not prepared to deal with front
end trees.
> thing is whether the simplification of the AST will change the
> control flow of a function and will affect the analysis on the
> CFG.
>
Nope. The only thing simplification does is break appart
convoluted expressions to expose side-effects and make the code
easier to analyze and transform. The resulting program is
semantically equivalent to the original.
>If I generate the data dependence graph of a function,can I
>utilize the reaching definition the tree-ssa branch has
>completed .thanks a lot.
>
Yes.
Diego.