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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/16331] x86-64 inline asm register constraints insufficient WRT ABI
Date: Tue, 10 Feb 2009 15:20:00 -0000	[thread overview]
Message-ID: <20090210152040.22625.qmail@sourceware.org> (raw)
In-Reply-To: <bug-16331-1331@http.gcc.gnu.org/bugzilla/>



------- Comment #14 from ubizjak at gmail dot com  2009-02-10 15:20 -------

> > OTOH, constraints should be used to support correct register
> > allocation for machine instructions, not to emulate ABI in order to
> > support calls from inside asm statements.
> 
> Please indulge me for a moment.
> 
> What exactly is a call?
> 
> Are you considering the only method of transferring control to be the
> standard 'near call' & 'near ret' instructions on the x86?

I was referring at the procedure call, where you need to setup outgoing
arguments on the calling point and setup incoming arguments on caller point.
gcc will magically match these two no matter what ABI-changing compile flag
(i.e. -mregparm) you use. When you call procedure from inside asm, gcc does not
know about that, and there is no way that gcc will know where arguments are to
be found.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16331


  parent reply	other threads:[~2009-02-10 15:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-16331-1331@http.gcc.gnu.org/bugzilla/>
2009-02-09 20:46 ` hjl dot tools at gmail dot com
2009-02-09 20:47 ` hjl dot tools at gmail dot com
2009-02-09 20:47 ` hjl dot tools at gmail dot com
2009-02-09 20:50 ` hjl dot tools at gmail dot com
2009-02-09 22:43 ` ubizjak at gmail dot com
2009-02-10 14:35 ` thutt at vmware dot com
2009-02-10 15:20 ` ubizjak at gmail dot com [this message]
2009-02-10 15:35 ` thutt at vmware dot com
     [not found] <bug-16331-4@http.gcc.gnu.org/bugzilla/>
2012-06-21 17:11 ` gcc at kalvdans dot no-ip.org
2014-06-25 23:48 ` gerald at pfeifer dot com
2004-07-02 16:51 [Bug c/16331] New: " thutt at vmware dot com
2004-08-03  7:06 ` [Bug target/16331] " pinskia at gcc dot gnu dot org
2005-07-02  1:27 ` pinskia at gcc dot gnu dot org
2005-07-02 10:17 ` falk at debian dot org
2005-09-04 19:05 ` pinskia at gcc dot gnu dot org

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