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From: "H. Peter Anvin" <hpa@zytor.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Ingo Molnar <mingo@elte.hu>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Fix immediate asm constraint for gcc 3 x86_64
Date: Fri, 16 May 2008 14:32:21 -0700	[thread overview]
Message-ID: <482DFD65.10300@zytor.com> (raw)
In-Reply-To: <20080516124811.GC4226@Krystal>

Mathieu Desnoyers wrote:

> 
> It seems that include/asm-x86/immediate.h in sched-devel.git causes
> this. gcc-3.4 does not seem to like the "i" (&name##__imv) constraint. I
> have seen no such problem with gcc-4.1. This is weird. It seems that
> relaxing the constraint helps fixing this, but it's not clear whether
> fixing the code or gcc-3.4 is the correct solution... here is the fix :
> 
> Fix immediate asm constraint for gcc 3 x86_64
> 

It might make it compile, but it's completely *wrong* for the purpose 
intended.

It permits gcc to present the address in a register, for example, so 
there is no guarantee that you end up with an immediate.

	-hpa

  reply	other threads:[~2008-05-16 21:36 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-14  9:54 x86-64 build problem with tip Jeremy Fitzhardinge
2008-05-16 12:48 ` [PATCH] Fix immediate asm constraint for gcc 3 x86_64 Mathieu Desnoyers
2008-05-16 21:32   ` H. Peter Anvin [this message]
2008-05-21 13:31     ` Mathieu Desnoyers
     [not found]       ` <48344239.9070003@zytor.com>
     [not found]         ` <20080521160217.GA26974@Krystal>
2008-05-21 17:01           ` [PATCH] Fix Immediate Values x86_64 support old gcc Mathieu Desnoyers
2008-05-21 20:37             ` Sam Ravnborg
2008-05-21 21:28               ` Mathieu Desnoyers
2008-05-21 21:46                 ` Sam Ravnborg
2008-05-21 21:57                   ` [PATCH] Fix Immediate Values x86_64 support old gcc (v2) Mathieu Desnoyers
2008-05-21 22:38                     ` Sam Ravnborg
2008-05-21 23:24                       ` [PATCH] Fix Immediate Values x86_64 support old gcc (v3) Mathieu Desnoyers
2008-05-22  2:03                         ` Mathieu Desnoyers
2008-05-25  7:21                           ` Sam Ravnborg
2008-05-27 13:12                             ` [PATCH ftrace.git sched-fixes.git] " Mathieu Desnoyers

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