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Re: simplify_subreg issues
- To: mark at codesourcery dot com
- Subject: Re: simplify_subreg issues
- From: Geoff Keating <geoffk at geoffk dot org>
- Date: Tue, 19 Jun 2001 22:48:30 -0700
- CC: kenner at vlsi1 dot ultra dot nyu dot edu, jh at suse dot cz, gcc at gcc dot gnu dot org
- References: <24580000.993074627@localhost.localdomain>
- Reply-to: Geoff Keating <geoffk at redhat dot com>
> Date: Wed, 20 Jun 2001 15:03:47 -0700
> From: Mark Mitchell <mark@codesourcery.com>
> cc: "kenner@vlsi1.ultra.nyu.edu" <kenner@vlsi1.ultra.nyu.edu>,
> "jh@suse.cz" <jh@suse.cz>, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
> Content-Disposition: inline
>
>
> > Think here of a hardware register, which is sensitive to 8-byte or
> > 4-byte accesses.
>
> Yeah -- but not a lot of hardware has registers that naturally store
> complex numbers.
>
> I wonder if we shouldn't just say that GCC makes no guarantees about the
> number of
> times something is accessed unless it is volatile and of one of the builtin
> C integer
> types. In pratice, that's what people usually care about. It might be
> better to
> make a limited promise that we could implement with confidence.
That sounds like a good idea. We could then _document_ what we think
'volatile' should mean!
--
- Geoffrey Keating <geoffk@geoffk.org>