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To: Adrian Bunk <bunk@stusta.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [-mm patch] i386: enable REGPARM by default
References: <20050515115712.GQ16549@stusta.de>
From: Andi Kleen <ak@muc.de>
Date: Sun, 15 May 2005 14:22:34 +0200
In-Reply-To: <20050515115712.GQ16549@stusta.de> (Adrian Bunk's message of
 "Sun, 15 May 2005 13:57:12 +0200")
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Adrian Bunk <bunk@stusta.de> writes:

> This patch should _not_ go into Linus' tree.
>
> At some time in the future, we want to unconditionally enable REGPARM on 
> i386.
>
> Let's give it a bit broader testing coverage among -mm users.

iirc problem is that gcc 2.95 and possibly 3.0.x have some known
miscompilations with regparams. That is why it was only used
with fastcall for a long time. One 3.1.x+ it should be safe.
But you cannot express dependencies on the compiler version
in Kconfig right now.

Of course getting rid of gcc 2.95 and 3.0.x support would be a good idea,
that would allow many other nice things.

-Andi