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Date: Tue, 17 Mar 1998 08:46:07 +0100
From: Thomas Koehler <T DOT Koehler AT pfh DOT research DOT philips DOT com>
Organization: Philips
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To: Paul Shirley <Paul AT chocolat DOT foobar DOT co DOT uk>
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Subject: Re: paranoia & extra precision
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Paul Shirley wrote:

> This puzzles me, in the past I have had to force various C compilers to
> keep intermediates on the fpu stack (by defining them as long doubles),
> even when optimising. Is a C compiler really allowed to make this change
> without explicit permission? (ie not just a general -On flag)

I agree, why else is there an explicit compiler switch 
 -ffast-math
              This option allows GCC to violate some ANSI or IEEE
              rules/specifications  in the interest of optimizing
              code for speed. 

Thomas
-- 



Thomas Koehler
Philips Research Laboratories
Division Technical Systems
Roentgenstrasse 24-26
D-22335 Hamburg
Germany

phone:  +40/5078-2103
e-mail: T DOT Koehler AT PFH DOT Research DOT Philips DOT com