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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] Adjust arch/powerpc inline asms for recent gcc change
Date: Fri, 30 Jul 2010 17:52:12 +1000	[thread overview]
Message-ID: <1280476332.2169.4.camel@pasglop> (raw)
In-Reply-To: <20100730071922.GQ18378@tyan-ft48-01.lab.bos.redhat.com>

On Fri, 2010-07-30 at 09:19 +0200, Jakub Jelinek wrote:
> So, in short, I'm afraid "m<>" needs to be used only for GCC 4.6+
> (and, vendors which backported the inline-asm handling changes
> to their older gcc would need to adjust for their gccs too).
> When "m<>" isn't used, it just leads to potential code pessimization
> in inline-asms that are prepared for handling side-effects. 

Ok, so we'll need some kind of macro to "fixup" those constraints ...

Just to make sure I understand things properly, if we don't change them,
the code will still be correct with 4.6 but sub-optimal, right ?

Cheers,
Ben.

      reply	other threads:[~2010-07-30  7:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-25  9:56 [PATCH] Adjust arch/powerpc inline asms for recent gcc change Jakub Jelinek
2010-06-25 11:08 ` Segher Boessenkool
2010-06-25 11:18   ` Jakub Jelinek
2010-06-30  6:10     ` Benjamin Herrenschmidt
2010-06-30 22:26       ` Segher Boessenkool
2010-07-08  6:08 ` Benjamin Herrenschmidt
2010-07-30  7:04   ` Benjamin Herrenschmidt
2010-07-30  7:19     ` Jakub Jelinek
2010-07-30  7:52       ` Benjamin Herrenschmidt [this message]

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