From:	Cees Wesseling <Wesseling AT frw DOT ruu DOT nl>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Optimize switch -O2 create FPU error
Date:	Tue, 17 Sep 1996 10:55:11 +0100
Organization:	Utrecht University
Lines:	23
Message-ID:	<323E757F.73B58D0@frw.ruu.nl>
References:	<323D96D7 DOT 5DA0 AT lem DOT ch DOT unito DOT it>
NNTP-Posting-Host:	holycow.frw.ruu.nl
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Carlo Nervi wrote:
> 
> my program works fine under djgpp v1.12, but exit with SIGFPE
> exception under djgpp v2.00. Using fsdb something strange happen:
> sometimes it exit with a Underflow exception, but sometime else
> running under fsdb the program runs, but with wrong numeric results.
> 
> Finally I was able to catch the problem: by using -O2 or -O3
> optimization switches the problem persist, whereas by using -O
> the problem disappear totally.
> Anybody had similar experience or it is due to a bug already solved
> which a don't know?
Yes, I did have the same problem, in a piece of code that has very
long and complicated expression. My guess is that this version of
gcc just flaws on the optimization. I simply wait for the next 
release. You might want to try some code re-arranging to solve the
problem.


-- 
 Cees Wesseling              | PO BOX 80.115   | 
 Dept. of Physical Geography | 3508 TC Utrecht | phone: (+31) 30 2532768   
 Utrecht University          | the Netherlands | fax:   (+31) 30 2540604

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