From: Samuel Rydh <samuel@ibrium.se>
To: Gabriel Paubert <paubert@iram.es>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: asm inline
Date: Fri, 29 Nov 2002 18:49:42 +0100 [thread overview]
Message-ID: <20021129174942.GA833@ibrium.se> (raw)
In-Reply-To: <Pine.LNX.4.33.0211291712010.9530-100000@gra-lx1.iram.es>
On Fri, Nov 29, 2002 at 05:21:50PM +0100, Gabriel Paubert wrote:
> On Fri, 29 Nov 2002, Samuel Rydh wrote:
> How is "addr" declared ? This may be an aliasing problem. Does adding
> -fno-strict-aliasing to the options help ? Or changing the "=m" to "+m" as
> an incorrect, but less penalizing than a memory clobber, bandaid. Or
> declaring addr as pointer to volatile ?
Turning of aliasing did indeed solve the problem. As did changing
unsigned long to int.
> > Adding "memory" to the clobber list seems to be the only way to make
> > gcc do the right thing :-(.
>
> A "memory" clobber is such an optimization killer that it is not
> acceptable in this situation (actually I consider a memory clober hardly
> ever acceptable).
Agreed. A "memory" clobber is definitely suboptimal.
> I see that your example involves local variables, does
> it also happen in the non-automatic case ?
It happens in the non-automatic case too. I'll try the
latest gcc version later.
/Samuel
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2002-11-29 17:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-29 16:08 asm inline Samuel Rydh
2002-11-29 16:21 ` Gabriel Paubert
2002-11-29 17:49 ` Samuel Rydh [this message]
2002-12-02 11:17 ` Franz Sirl
2002-12-02 13:11 ` Samuel Rydh
2002-12-02 13:35 ` Andreas Schwab
2002-12-02 14:14 ` Kevin B. Hendricks
2002-12-02 14:29 ` Andreas Schwab
2002-12-02 14:37 ` Kevin B. Hendricks
2002-12-02 14:51 ` Franz Sirl
2002-12-02 15:08 ` Kevin B. Hendricks
2002-12-02 15:11 ` Kevin B. Hendricks
2002-12-02 15:35 ` Franz Sirl
2002-12-02 15:45 ` Kevin B. Hendricks
2002-12-02 15:12 ` Franz Sirl
2002-12-02 17:00 ` Samuel Rydh
2002-12-02 17:53 ` Gabriel Paubert
2002-12-02 19:17 ` Samuel Rydh
2002-11-29 16:30 ` Benjamin Herrenschmidt
2002-12-02 14:29 ` Gabriel Paubert
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