Date: Thu, 22 Feb 2007 04:50:39 -0500
From: Jakub Jelinek <jakub@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Arjan van de Ven <arjan@infradead.org>, Andi Kleen <ak@muc.de>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: -freg-struct-return?
Message-ID: <20070222095039.GR10425@devserv.devel.redhat.com>
Reply-To: Jakub Jelinek <jakub@redhat.com>
References: <45DCF1C5.4030006@goop.org> <1172131463.3531.226.camel@laptopd505.fenrus.org> <45DD4FA0.5030205@goop.org>
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On Thu, Feb 22, 2007 at 12:09:04AM -0800, Jeremy Fitzhardinge wrote:
> Arjan van de Ven wrote:
> > Do we know how many gcc bugs this has? (regparm used to have many)
> > other than that.. sounds like a win...
> >   
> 
> The documentation suggests that its the preferred mode of operation, and
> that its the default on platforms where gcc is the primary compiler.  So
> the fact that it isn't for Linux suggests either an oversight or that it
> is actually broken...

It is used for Linux on many architectures (x86_64, sparc64, ia64,
ppc{,64}, arm, sh, m68k to name just a few), but it is an ABI decision,
so e.g. on i386 is not used by default as the ABI mandates structs/unions
are returned in memory.

	Jakub
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