This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Dead-code elimination can't remove string copy insns?
- From: Michael Matz <matz at suse dot de>
- To: Richard Henderson <rth at redhat dot com>
- Cc: Zack Weinberg <zack at codesourcery dot com>, <gcc at gcc dot gnu dot org>
- Date: Wed, 14 May 2003 11:25:21 +0200 (CEST)
- Subject: Re: Dead-code elimination can't remove string copy insns?
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.