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Re: [tree-ssa]: Easy way to get default def of a variable?
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Andrew Macleod <amacleod at redhat dot com>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: 05 Jun 2003 13:54:24 -0400
- Subject: Re: [tree-ssa]: Easy way to get default def of a variable?
- Organization: Red Hat Canada
- References: <9D2E10A2-9775-11D7-937C-000A95A34564@dberlin.org>
On Thu, 2003-06-05 at 12:49, Daniel Berlin wrote:
> I don't know it's a_5, that's the problem.
> Let me be more concrete:
> In this case, we generate saves where we see expression phi operands
> that have no actual occurrence associated with them yet (IE they need a
> real expression save to back them up, but a usable one isn't there
> already).
> Thus, I need to figure out what version to use in the save.
> We do this by walking up the dominator tree, looking for the closest
> reaching def of the variable.
> If there is none, after hitting the entry block, it must be live on
> entry, and i need the default def.
>
Sorry Dan, I'm totally lost. Could you show the code for the actual
test case you're talking about? I just don't see what problem you're
trying to solve.
Thanks. Diego.