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Re: SSA usage question
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Mon, 07 Jun 2004 13:02:13 -0400
- Subject: Re: SSA usage question
- Organization: Red Hat Canada
- References: <10406071641.AA10883@vlsi1.ultra.nyu.edu>
On Mon, 2004-06-07 at 12:41, Richard Kenner wrote:
> These things can change from reference to reference? That is,
> given the array 'a' above, will every reference to 'a' use a
> potentially different 'x' and 'v'?
>
> No. They are the unchanging over the lifetime of an object. If the
> type has placeholders, then it may be different between two objects of
> the same type, though.
>
OK, if the values are anything other than constants, then we need to go
out of our way to express them as IL statements. I thought these values
were actual constants and were the same for every object of the same
type (like they are in C).
Having them change inside a type attribute in ways not obvious to the
optimizers is asking for trouble.
Diego.