From: "Ondřej Bílka" <neleai@seznam.cz>
To: Siddhesh Poyarekar <siddhesh@redhat.com>
Cc: libc-alpha@sourceware.org, libc-ports@sourceware.org
Subject: Re: [PATCH][BZ #14412] Define __sincos_finite as a fast version of sincos
Date: Tue, 30 Apr 2013 08:59:00 -0000 [thread overview]
Message-ID: <20130430085800.GA31516@domone.kolej.mff.cuni.cz> (raw)
In-Reply-To: <20130429102739.GE1330@spoyarek.pnq.redhat.com>
On Mon, Apr 29, 2013 at 03:57:40PM +0530, Siddhesh Poyarekar wrote:
> Hi,
>
> The assembly implementation of sincos on x86_64 was removed in favour
> of the default implementation since the former was inaccurate for some
> inputs. This led to BZ #14412 being reported for a performance
> regression in sincos.
>
> This patch brings back the assembly implementation of sincos (with
> some changes) to give a fast alternative to the default sincos
> implementation. This is defined as __sincos_finite and is used if the
> implementing program is compiled with the -ffinite-math-only gcc flag.
>
Could you add test that input is less than 1000 and 1/1000 away from
multiple of pi? If so call precise version.
Assembly should be precise on these inputs so you do not have to add
-ffast math hack.
> I have tested that this works correctly for x86_64 and i686, where the
> former uses the assembly implementation of __sincos_finite and the
> latter uses the weak alias to sincos. I have also verified that there
> are no regressions in the testsuite on x86_64.
>
> The patch also has changes to m68k and ia64 (in addition to the
> abilist update) since they have custom implementations of sincos. I
> have not tested those, so I would request the maintainers to let me
> know if the changes break anything on their architectures.
>
> Siddhesh
>
next prev parent reply other threads:[~2013-04-30 8:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 10:26 Siddhesh Poyarekar
2013-04-29 13:31 ` Andreas Schwab
2013-04-29 13:34 ` Joseph S. Myers
2013-04-29 14:02 ` Siddhesh Poyarekar
2013-04-29 14:16 ` Ondřej Bílka
2013-04-29 14:53 ` Andrew Haley
2013-04-29 15:19 ` Rich Felker
2013-04-30 8:59 ` Ondřej Bílka [this message]
2013-04-30 9:03 ` Siddhesh Poyarekar
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