From: Christoph Hellwig <hch@caldera.de>
To: Corey Minyard <minyard@acm.org>
Cc: gcc@gcc.gnu.org
Subject: Re: Optimizations on long long multiply/divide on PowerPC32 don't work
Date: Mon, 10 Dec 2001 09:09:00 -0000 [thread overview]
Message-ID: <20011210180709.A10139@caldera.de> (raw)
In-Reply-To: <3C115A53.2070206@acm.org>; from minyard@acm.org on Fri, Dec 07, 2001 at 06:09:55PM -0600
On Fri, Dec 07, 2001 at 06:09:55PM -0600, Corey Minyard wrote:
> I can see four options to solve this problem:
>
> 1) Add __divdi3 to the linux kernel. I don't really think this is a
> good idea, and it shouldn't be required.
> 2) Move the conversion of the division to the function call to the
> very last stages of the compiler. IMHO, this is probably the best
> option, but it's a big job to implement, I think.
> 3) Make the optimizations understand the function calls. I don't even
> want to think about this one.
> 4) Modify the tree conversions to do the optimizations there. I have
> a patch that does this (and passes all regressions), because it was
> easy, but I consider it less optimal than option 2.
Fix that code to use shifts instead. As far as I can see that's general
linux kernel practice.
Christoph
--
Of course it doesn't work. We've performed a software upgrade.
next prev parent reply other threads:[~2001-12-10 17:09 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-07 16:08 Corey Minyard
2001-12-07 17:08 ` Richard Henderson
2001-12-07 17:40 ` Corey Minyard
2001-12-09 23:29 ` Linus Torvalds
2001-12-10 1:15 ` Richard Henderson
2001-12-10 1:24 ` Richard Henderson
2001-12-10 2:40 ` Franz Sirl
2001-12-10 9:21 ` Linus Torvalds
2001-12-10 10:59 ` Franz Sirl
2001-12-10 11:11 ` Linus Torvalds
2001-12-10 11:31 ` Gabriel Paubert
2001-12-10 17:58 ` Richard Henderson
2002-01-22 8:51 ` Franz Sirl
2002-01-22 12:04 ` Richard Henderson
2002-01-23 7:24 ` Gerald Pfeifer
2002-02-03 10:44 ` Franz Sirl
2001-12-10 9:15 ` Linus Torvalds
2001-12-10 13:03 ` Richard Henderson
2001-12-10 13:59 ` Linus Torvalds
2001-12-10 9:09 ` Paul Koning
2001-12-10 10:23 ` Linus Torvalds
2001-12-10 11:35 ` Optimizations on long long multiply/divide on PowerPC32 don't Joe Buck
2001-12-10 13:49 ` guerby
2001-12-10 14:08 ` Arnaud Charlet
2001-12-10 14:31 ` guerby
2001-12-10 9:09 ` Christoph Hellwig [this message]
2001-12-07 18:28 Optimizations on long long multiply/divide on PowerPC32 don't work mike stump
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