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Re: [tree-ssa] where to fix this?
- From: law at redhat dot com
- To: Jan Hubicka <jh at suse dot cz>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Roger Sayle <roger at eyesopen dot com>, Dale Johannesen <dalej at apple dot com>, gcc at gcc dot gnu dot org
- Date: Tue, 06 Jan 2004 11:53:26 -0700
- Subject: Re: [tree-ssa] where to fix this?
- Reply-to: law at redhat dot com
In message <20040106184856.GM6383@kam.mff.cuni.cz>, Jan Hubicka writes:
>I don't think the idea of actually doing the folding and then testing
>whether it is valid is good. It costs memory and folder may get to be
>over-active stepping out of allowed ground missing allowed
>transformation as commonly happens for combine.
There's certainly times when I'm going to want to give fold a fairly
complex expression, but I'm going to want to know if the result of folding
that complex non-gimple expression results in a gimple expression. That
can either be done in all the callers or it can be controlled by passing
a flag/callback to the folder.
Given that we already have a couple places where we need this, I'd prefer
to have this behavior in the folder itself, controlled by the caller setting
the right flag and/or callback.
>Also how callback "it is valid transformation according to C standard"
>can be implemented? It still has to know all the transformations C
The callback is set up by the front-end to call a front-end routine.