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From: Geoff Keating <geoffk@geoffk.org>
To: Jan Hubicka <jh@suse.cz>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: Simplify floating point conversions
Date: Tue, 05 Nov 2002 11:14:00 -0000	[thread overview]
Message-ID: <jm4ravommn.fsf@desire.geoffk.org> (raw)
In-Reply-To: <20021105171400.GX14655@kam.mff.cuni.cz>

Jan Hubicka <jh@suse.cz> writes:

> Hi,
> this patch makes us to simplify some of the floating point operations to
> narrower mode when conversions are present.  This include
> +,-,/,*,abs,neg,sqrt/sin/cos/exp.
> I believe it is IEEE safe, but some expert would be welcome.

It's not safe, except for 'abs' and 'neg'.  For example,
(float)sqrt(2.0 * FLT_MAX) != sqrtf(2.0 * FLT_MAX).
I think it would be OK for -ffast-math, though.

-- 
- Geoffrey Keating <geoffk@geoffk.org>

  parent reply	other threads:[~2002-11-05 19:14 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-11-05  9:14 Jan Hubicka
2002-11-05  9:38 ` Richard Henderson
2002-11-05  9:42   ` Jan Hubicka
2002-11-06  1:23   ` Simplify floating point conversions II Jan Hubicka
2002-11-06  3:08     ` Michael Matz
2002-11-06  4:36       ` Jan Hubicka
2002-11-06  9:54     ` Jan Hubicka
2002-11-06 10:09       ` Richard Henderson
2002-11-06 13:11         ` Jan Hubicka
2002-11-06 13:19           ` Jan Hubicka
2002-11-06 13:35           ` Gabriel Dos Reis
2002-11-06 13:36             ` Jan Hubicka
2002-11-06 14:06               ` Gabriel Dos Reis
2002-11-06 14:29             ` Converting floor to rint Jan Hubicka
2002-11-06 14:47               ` Richard Henderson
2002-11-06 14:53                 ` Jan Hubicka
2002-11-06 14:55               ` Gabriel Dos Reis
2002-11-07  1:21                 ` Jan Hubicka
2002-11-07  1:32                   ` Jakub Jelinek
2002-11-07  1:33                   ` Gabriel Dos Reis
2002-11-07  1:44                     ` Jan Hubicka
2002-11-07  1:52                       ` Jakub Jelinek
2002-11-07  1:54                         ` Jan Hubicka
2002-11-07  2:04                     ` Jan Hubicka
2002-11-07  4:47                       ` Gabriel Dos Reis
2002-11-07  4:56                         ` Jan Hubicka
2002-11-07  5:14                           ` Andreas Schwab
2002-11-07  5:27                             ` Gabriel Dos Reis
2002-11-07  5:31                               ` Jan Hubicka
2002-11-07  5:35                                 ` Andreas Schwab
2002-11-07  5:22                           ` Gabriel Dos Reis
2002-11-07  5:43                             ` Andreas Schwab
2002-11-07  6:23                               ` Gabriel Dos Reis
2002-11-07  7:01                                 ` Jan Hubicka
2002-11-07  7:18                                   ` Gabriel Dos Reis
2002-11-06 13:48         ` Simplify floating point conversions III Jan Hubicka
2002-11-06 14:55           ` Richard Henderson
2002-11-07  2:54             ` Simplify floating point conversions IV Jan Hubicka
2002-11-18 15:01               ` Richard Henderson
2002-11-05 11:14 ` Geoff Keating [this message]
2002-11-06  1:09   ` Simplify floating point conversions Jan Hubicka

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