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Re: [tree-ssa] Lazy updating of stmt operands
- From: law at redhat dot com
- To: Andrew MacLeod <amacleod at redhat dot com>
- Cc: Chris Lattner <sabre at nondot dot org>, Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Mon, 15 Dec 2003 16:36:10 -0700
- Subject: Re: [tree-ssa] Lazy updating of stmt operands
- Reply-to: law at redhat dot com
In message <1071323157.3257.138.camel@p4>, Andrew MacLeod writes:
>The Cache isnt something we're trying to work around. Thats there to
>prevent us from having to muck around in trees looking for things which
>are operands. The stmt is in the form of trees, our "cache" is the
>equivilent of your instruction. It consists of the operands plus looking
>at the tree code(s) of the stmt.
>
>So we have 1 word for each operand. It points to the SSA_NAME in the
>stmt tree which represents that ssa version.
>
>As far as Im concerned, we're not working around anything. Everything
>works just fine. IF someone wants/needs the def->use inforation, it can
>be built today. What we dont have is the ability to keep it up to date
>for some period of time, simply because we've never needed it. If the
>time comes that we do need it, it is not hard to add.
In fact, we could even ponder the idea of what we now know as the operand
cache morphing into a lighter-weight IL at some point in the future.
Jeff