From: Anton Blanchard <anton@samba.org>
To: Dave Jones <davej@suse.de>, "David S. Miller" <davem@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: results: Remove 8 bytes from struct page on 64bit archs
Date: Mon, 14 Jan 2002 17:35:31 +1100 [thread overview]
Message-ID: <20020114063531.GC18794@krispykreme> (raw)
In-Reply-To: <20020106.060824.106263786.davem@redhat.com> <Pine.LNX.4.33.0201061542450.3859-100000@Appserv.suse.de> <20020107012555.GA6623@krispykreme> <20020106192204.B27356@twiddle.net>
In-Reply-To: <20020106192204.B27356@twiddle.net>
> The powerpc backend claims to have a fast divide instruction
> (via RTX_COST if you care about such things). We'll replace
> with shift when dividing by powers of 2, but won't try the
> multiply by a constant inverse trick.
To follow up: Alan Modra found and fixed the bug, it seems we were only
using the optimisation when the arguments were <= 32bit.
The target we use is RS64a which has a cost of 60 odd instructions
for divide.
Anton
next prev parent reply other threads:[~2002-01-15 0:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-06 12:39 [PATCH] Remove 8 bytes from struct page on 64bit archs Anton Blanchard
2002-01-06 13:02 ` Horst von Brand
2002-01-06 13:07 ` Dave Jones
2002-01-06 13:13 ` Momchil Velikov
2002-01-06 13:25 ` Dave Jones
2002-01-06 13:28 ` William Lee Irwin III
2002-01-06 14:08 ` David S. Miller
2002-01-06 14:44 ` Dave Jones
2002-01-07 1:25 ` results: " Anton Blanchard
2002-01-07 3:22 ` Richard Henderson
2002-01-14 6:35 ` Anton Blanchard [this message]
2002-01-15 0:45 ` Dave Jones
2002-01-07 5:13 ` David S. Miller
2002-01-06 13:11 ` [PATCH] " William Lee Irwin III
2002-01-06 13:33 ` Anton Blanchard
2002-01-06 13:51 ` William Lee Irwin III
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