Date: Wed, 28 Dec 2005 13:47:04 +0100
From: Sam Ravnborg <sam@ravnborg.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, lkml <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
       Arjan van de Ven <arjan@infradead.org>, Matt Mackall <mpm@selenic.com>
Subject: Re: [patch 02/2] allow gcc4 to optimize unit-at-a-time
Message-ID: <20051228124704.GA9503@mars.ravnborg.org>
References: <20051228114701.GC3003@elte.hu> <20051228120435.GS22293@devserv.devel.redhat.com> <20051228122815.GA9365@mars.ravnborg.org> <20051228130435.GU22293@devserv.devel.redhat.com>
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On Wed, Dec 28, 2005 at 08:04:35AM -0500, Jakub Jelinek wrote:
> No.
> -fno-unit-at-a-time should be used with GCCs that
> a) support it
> b) are older than GCC 4.0
> 
> The "$(GCC_VERSION) -lt 0400" test cares of b),
> $(call cc-option,-fno-unit-at-a-time) cares of a).

There was a reason for disabling it unconditionally in first place.
That was due to unexpected huge stack usage if I understand correct.
Ingo's patch enebles unit-at-a-time only for gcc > 4.00 which should
have this issue fixed.

If the argument is that we suddenly shall enable unit-at-a-time for
gcc before 4.00 then we should visit the reasons why it originally was
disabled.

	Sam
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