From: Andrew Haley <aph@redhat.com>
To: gcc-help@gcc.gnu.org
Subject: Re: gcc optimises out test of value in register-only loop
Date: Fri, 14 Oct 2011 09:07:00 -0000 [thread overview]
Message-ID: <4E97FBC1.9080006@redhat.com> (raw)
In-Reply-To: <mcrobxk6v7l.fsf@coign.corp.google.com>
On 10/14/2011 05:41 AM, Ian Lance Taylor wrote:
> MikeW <mw_phil@yahoo.co.uk> writes:
>
>> volatile register int stop_loop __asm("r5")__;
>
> gcc does not support volatile register variables. I think it could be
> meaningful, but it has never worked.
It would be really nasty to implement: we'd have to check for volatility
on every access to a hard register. The benefits don't seem worth it,
IMO.
Andrew.
next prev parent reply other threads:[~2011-10-14 9:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-13 11:35 MikeW
2011-10-13 11:38 ` Andrew Haley
2011-10-13 11:56 ` MikeW
2011-10-13 11:58 ` Thomas Martitz
2011-10-13 12:01 ` Andrew Haley
2011-10-13 12:14 ` MikeW
2011-10-13 12:18 ` Andrew Haley
2011-10-13 12:05 ` MikeW
2011-10-14 4:41 ` Ian Lance Taylor
2011-10-14 9:07 ` Andrew Haley [this message]
2011-10-15 3:20 ` Ian Lance Taylor
2011-10-17 8:30 ` Andrew Haley
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