This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: simplify_subreg issues
- To: Geoff Keating <geoffk at redhat dot com>
- Subject: Re: simplify_subreg issues
- From: Mark Mitchell <mark at codesourcery dot com>
- Date: Mon, 11 Jun 2001 21:39:36 -0700
- cc: "kenner at vlsi1 dot ultra dot nyu dot edu" <kenner at vlsi1 dot ultra dot nyu dot edu>, "jh at suse dot cz" <jh at suse dot cz>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
> The underlying problem is that 'volatile' doesn't make sense in
> conjunction with 'complex'. We can't do complex loads or stores. So,
> actually in this case the optimisation would be correct, because what
> we want to have is
>
> (set (mem/v:SF ...) ...)
>
I don't really understand what we do with `volatile' on a structure
type, in general, or what the standard says we have to do.
I guess one would like to avoid `f(y)' -- where `y' is some
volatile complex type -- generating more than one reference to any
word in `y'.
Are you saying that the use of `MEM_VOLATILE_P' is unncessary here,
or that the MEM should nont be volatile, or that the MEM_VOLATILE_P
test should be done only in conjuction with some additional check
that says `and is not a complex type'?
Thanks,
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com