Mail Archives: djgpp/1999/12/09/09:40:26

Date: Thu, 9 Dec 1999 16:05:46 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: George Ryot <ryot AT bigfoot DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: fftw give nonsense with float ok with double
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On Wed, 8 Dec 1999, George Ryot wrote:

> Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:
> >  2. Why do you use -O3?  If you don't have any special reason, try -O2
> >     instead, it usually yields better results anyway.
> I am wondering in what way does -O2 yield better results than -O3, are
> you refering to code size or is there another consideration?

No, I meant speed.  In many cases, -O2 yields a faster program, the usual 
cause being code cache overflow.

In addition, -O2 is much better tested, since it is the usual 
optimization level, so many programs, including the compiler itself, are 
compiled with it.  Therefore, bugs are less probable to happen with -O2.

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