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Date: Mon, 21 Mar 2011 10:52:00 -0000
Message-ID: <AANLkTikYxVzFjLQFNvEy2FBmuO76PJPA5JuLgoUGzPF0@mail.gmail.com>
Subject: Re: X32 psABI status update
From: "H.J. Lu" <hjl.tools@gmail.com>
To: Michael Matz <matz@suse.de>
Cc: Mike Frysinger <vapier@gentoo.org>, libc-alpha@sourceware.org, 	GCC Development <gcc@gcc.gnu.org>, LKML <linux-kernel@vger.kernel.org>, x32-abi@googlegroups.com
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On Mon, Mar 21, 2011 at 1:20 AM, Michael Matz <matz@suse.de> wrote:
> Hi,
>
> On Sun, 20 Mar 2011, H.J. Lu wrote:
>
>> I don't think it will help x32 and I think it will make it harder to add
>> x32 support. I still want to see a real usage before I add it.
>
> % cat real-world.c
> /* intptr_t; what's that? */
> union space_saving_htab_element {
> =A0void *generic_pointer;
> =A0/* Usually we need a long for a pointer, but I just figured out
> =A0 =A0 that on x32 an int is enough and smaller. =A0My program
> =A0 =A0 now needs half as much memory, supi! =A0*/
> #ifdef __x32__
> =A0unsigned int as_number;
> #else
> =A0unsigned long as_number;
> #endif
> };

That is the wrong way to support x32.  You should remove "#ifdef __x32__",
which only shows __x32__ shouldn't be used/needed.

>
> Ciao,
> Michael.
> PS: Of course you and I wouldn't write such code, but Mikes point was that
> there might be some that do. =A0I could probably construct an example whe=
re
> it would matter for real involving inline asm that for some reason has to
> slightly differ depending on x32-ness.
>

I  am still waiting for a real example.

--=20
H.J.