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
Date: Wed, 28 Dec 2005 13:47:04 +0100 [thread overview]
Message-ID: <20051228124704.GA9503@mars.ravnborg.org> (raw)
In-Reply-To: <20051228130435.GU22293@devserv.devel.redhat.com>
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
next prev parent reply other threads:[~2005-12-28 13:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-28 11:47 [patch 02/2] allow gcc4 to optimize unit-at-a-time Ingo Molnar
2005-12-28 12:04 ` Jakub Jelinek
2005-12-28 12:28 ` Sam Ravnborg
2005-12-28 13:04 ` Jakub Jelinek
2005-12-28 12:47 ` Sam Ravnborg [this message]
2005-12-28 12:50 ` Sam Ravnborg
2005-12-28 13:06 ` Ingo Molnar
2005-12-28 15:30 ` Andi Kleen
2005-12-28 15:34 ` Matt Mackall
2005-12-28 15:41 ` Ingo Molnar
2005-12-28 17:46 ` Andreas Kleen
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