From: "H. J. Lu" <hjl@lucon.org>
To: James E Wilson <wilson@specifixinc.com>
Cc: gcc@gcc.gnu.org
Subject: Re: Redundant instructions in loop optimization for x86-64?
Date: Fri, 10 Sep 2004 23:44:00 -0000 [thread overview]
Message-ID: <20040910220754.GA13666@lucon.org> (raw)
In-Reply-To: <414211DD.5030900@specifixinc.com>
On Fri, Sep 10, 2004 at 01:43:09PM -0700, James E Wilson wrote:
> H. J. Lu wrote:
> >Is there a way to tell gcc that 32bit zero extension isn't needed for
> >x86-64?
>
> It isn't quite that simple. Sometimes they will be needed. Sometimes
> they won't.
>
> You might want to look at
> http://gcc.gnu.org/ml/gcc/2004-09/msg00377.html
> which is a proposal to add an RTL optimization pass to eliminate
> unnecessary sign/zero extension instructions on targets that support
> both 32-bit and 64-bit code.
Is there a version which will apply to the current source tree?
H.J.
next prev parent reply other threads:[~2004-09-10 22:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-10 0:22 H. J. Lu
2004-09-10 10:17 ` Jan Hubicka
2004-09-10 17:35 ` H. J. Lu
2004-09-10 22:15 ` James E Wilson
2004-09-10 23:44 ` H. J. Lu [this message]
2004-09-11 0:10 ` James E Wilson
2004-09-11 1:58 ` Jan Hubicka
2004-09-11 11:51 ` Jan Hubicka
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