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Date: Wed, 14 May 2003 09:25:00 -0000
From: Michael Matz <matz@suse.de>
To: Richard Henderson <rth@redhat.com>
Cc: Zack Weinberg <zack@codesourcery.com>, <gcc@gcc.gnu.org>
Subject: Re: Dead-code elimination can't remove string copy insns?
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Hi,

On Tue, 13 May 2003, Richard Henderson wrote:

> On Tue, May 13, 2003 at 11:30:12AM +0200, Michael Matz wrote:
> > Exactly.  We don't track dead stores to memory.
>
> Well, we do, but it only works on tail blocks.

I know.  But this uses the mem expressions to represent the stored-into
memory, and hence doesn't work on BLKmode mems.  I guess one could special
case Zacks example by noting (for the tail blocks), that all stores to
stack mem are dead if there is _no_ read from stack afterwards.  But this
special casing quickly becomes silly.


Ciao,
Michael.