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Re: Questions about "Handle constant exponents." in gcc/builtins.c

From: Vincent Lefevre <vincent+gcc at vinc17 dot org>
To: gcc at gcc dot gnu dot org
Date: Thu, 18 Mar 2010 15:10:01 +0100
Subject: Re: Questions about "Handle constant exponents." in gcc/builtins.c
References: <20100316151100.BD92D3BE0F@mailhost.lps.ens.fr> <84fc9c001003160818o230920eei84f0558a81fdcf7@mail.gmail.com> <20100318134339.GC1758@prunille.vinc17.org>

On 2010-03-18 14:43:39 +0100, Vincent Lefevre wrote:
> This violates the ISO C99 standard for -0.0.
> 
> According to N1256, F.9.4.4:
> 
>   pow(±0, y) returns +0 for y > 0 and not an odd integer.
> 
> So, pow(-0.0, 0.5) should return +0. But sqrt(-0.0) should return -0
> according to the IEEE 754 standard (and F.9.4.5 from ISO C99).

I've reported the problem:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)

References:
- Questions about "Handle constant exponents." in gcc/builtins.c
  - From: Dominique Dhumieres
- Re: Questions about "Handle constant exponents." in gcc/builtins.c
  - From: Richard Guenther
- Re: Questions about "Handle constant exponents." in gcc/builtins.c
  - From: Vincent Lefevre

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