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Re: SSA usage question
- From: Richard Henderson <rth at redhat dot com>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 6 Jun 2004 16:25:27 -0700
- Subject: Re: SSA usage question
- References: <10406062305.AA02937@vlsi1.ultra.nyu.edu>
On Sun, Jun 06, 2004 at 07:05:42PM -0400, Richard Kenner wrote:
> What we will NOT do is have implicit variable references.
> Of any kind. This is not open to discussion.
>
> Of course it's open for discussion!
Implicit references cannot be put into SSA form, and thus cannot
be put through the tree optimizer at all. QED.
> It's simply not an acceptable approach to throw away all typing, aliasing and
> array structure implementation just because there's a variable size, lower
> bound, or position involved.
That's what rtl did. I don't see that we're really doing anything
different. Yes, we could do *better* if we figured out *some other*
representation that preserved information longer, but I really don't
believe we'll do significantly worse in the mean time.
r~