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Re: [tree-ssa] Maintaining/representing def-use/use-def information
- From: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- To: Chris Lattner <sabre at nondot dot org>
- Cc: Andrew MacLeod <amacleod at redhat dot com>, Jeff Law <law at redhat dot com>,gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Mon, 15 Dec 2003 22:14:22 +0100
- Subject: Re: [tree-ssa] Maintaining/representing def-use/use-def information
- References: <1071521234.3257.1817.camel@p4> <Pine.LNX.4.44.0312151502130.27073-100000@nondot.org>
Hello,
> No, we don't. We don't have any concept of "defining variable" or
> "versions" at all. Though all SSA construction papers talk about building
> versions of source variables, once you start doing transformations, that
> idea becomes quickly meaningless.
except for ssa-pre, that requires the original variable names. I still
consider it an indication that there is something rotten with the
optimization, but did not get the idea how to make it better so far.
Zdenek