This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: RFC: x86: Emit rsqrt with only -ffast-math

From: Michael Matz <matz at suse dot de>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: gcc-patches at gcc dot gnu dot org
Date: Thu, 5 Nov 2009 15:12:22 +0100 (CET)
Subject: Re: RFC: x86: Emit rsqrt with only -ffast-math
References: <Pine.LNX.4.64.0911031425320.15566@wotan.suse.de> <84fc9c000911030553h4899dd89i461e6ea891e1c18e@mail.gmail.com>

Hi,

On Tue, 3 Nov 2009, Richard Guenther wrote:

> Thus, I'm ok with that if the target maintainers agree.  I think this 
> needs a documentation update to mrecip though.

r153940.  I've added this sentence to the -mrecip docu:

+Note that GCC implements 1.0f/sqrtf(x) in terms of RSQRTSS (or RSQRTPS)
+already with @option{-ffast-math} (or the above option combination), and
+doesn't need @option{-mrecip}.


Ciao,
Michael.

References:
- RFC: x86: Emit rsqrt with only -ffast-math
  - From: Michael Matz
- Re: RFC: x86: Emit rsqrt with only -ffast-math
  - From: Richard Guenther

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]