From: Andrew Morton <akpm@linux-foundation.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Chanho Min <chanho.min@lge.com>,
Kyungsik Lee <kyungsik.lee@lge.com>,
Yann Collet <yann.collet.73@gmail.com>,
Bob Pearson <rpearson@systemfabricworks.com>,
Richard Weinberger <richard@nod.at>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
sparclinux <sparclinux@vger.kernel.org>,
Linux/m68k <linux-m68k@vger.kernel.org>,
Linux-Next <linux-next@vger.kernel.org>
Subject: Re: [PATCH] lib: add weak __clzsi2()/__clzdi2() functions
Date: Tue, 30 Apr 2013 14:46:05 -0700 [thread overview]
Message-ID: <20130430144605.1a99a7397702b332ee818fc8@linux-foundation.org> (raw)
In-Reply-To: <CAMuHMdWk4oi_KCmZv7hLZ7JSwy=meziKPBMQ1HJiJR9W8AdrDg@mail.gmail.com>
On Mon, 29 Apr 2013 09:20:25 +0200 Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Mon, Apr 29, 2013 at 7:40 AM, Chanho Min <chanho.min@lge.com> wrote:
> > Some architectures need __clzsi2() or __clzdi2() for __builtin_clz and
> > It causes build failure. They can be implemented using the fls() and
> > overridden by linking arch-specific versions may not be implemented yet.
> >
> > Reference: https://lkml.org/lkml/2013/4/18/603
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Signed-off-by: Chanho Min <chanho.min@lge.com>
>
> Thanks, this fixes the link error on m68k, so
>
> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
It doesn't work for alpha (gcc-4.4.4):
ERROR: "__ctzdi2" [lib/lz4/lz4hc_compress.ko] undefined!
ERROR: "__ctzdi2" [lib/lz4/lz4_compress.ko] undefined!
akpm3:/usr/src/25> nm vmlinux|grep ctzd
akpm3:/usr/src/25>
I assume the linker threw the code away.
How's about we stop using __builtin_ctz[ll]() altogether? Use N-fls()?
btw, this:
int __weak __clzsi2(int val)
{
return BITS_PER_LONG - fls(val);
}
looks wrong. It will give a different result for 32- and 64-bit.
next prev parent reply other threads:[~2013-04-30 21:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 5:40 [PATCH] lib: add weak __clzsi2()/__clzdi2() functions Chanho Min
2013-04-29 7:20 ` Geert Uytterhoeven
2013-04-30 21:46 ` Andrew Morton [this message]
2013-05-01 7:35 ` Geert Uytterhoeven
2013-05-02 0:58 ` 민찬호
2013-04-30 19:47 ` Andrew Morton
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