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Re: gcc 3.1 is still very slow, compared to 2.95.3
- From: law at redhat dot com
- To: "David S. Miller" <davem at redhat dot com>
- Cc: jh at suse dot cz, neil at daikokuya dot demon dot co dot uk, jseward at acm dot org, gcc at gcc dot gnu dot org, njn25 at cam dot ac dot uk
- Date: Sun, 19 May 2002 09:29:16 -0600
- Subject: Re: gcc 3.1 is still very slow, compared to 2.95.3
- Reply-to: law at redhat dot com
In message <email@example.com>, "David S. Miller" write
> From: Jan Hubicka <firstname.lastname@example.org>
> Date: Sun, 19 May 2002 14:17:50 +0200
> > The Sparc output is very perplexing because GCC eliminated one of
> > the byte stores that overlapped the store of "code" but not both
> > of them!
> :) I think this is present in the flow.c dead store ellimination - it che
> address for equivalence.
> Looks like we have discovered a bug in dead store elimination :-)
The generic DSE code only eliminates stores where the address expressions
are identical -- so it would not eliminate a byte store that is subsumed by
a word store.
I don't think adding that capability would be all that difficult.