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Re: Strange g+ 3.1.1 double behavior
- From: Michael Veksler <veksler at il dot ibm dot com>
- To: Gunther Weber <weber at informatik dot uni-kl dot de>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 06 Aug 2002 13:39:35 +0300
- Subject: Re: Strange g+ 3.1.1 double behavior
- Reply-to: veksler at il dot ibm dot com
References: <3D4E8656.email@example.com> <3D4E889D.243FAFCB@acm.org>
Gunther Weber wrote:
Thank you for your answer. That explains how this problem occurs.
-float-store (-mfloat-store does not exist) does not help, but
|-mno-fp-ret-in-387 helps. Anyway, I will not use these options. Insted
I will get rid of my misconception that identical floating point
calculations yield identical results and |write my programs accordingly.
So thank you for explaining this to me as it may help to prevent future
grief that would have resulted from holding on to my misconception :-)
I think you were correct to assume that FP calculations should yield
identical results. This is true at least according to IEEE standard.
Some time ago I had a similar complaint:
At the end of this page you can find a solution to your problem.
Also, it contains an explanation why I think current behavior is wrong
(the gcc/glibc combination does something wrong thing with FP arithmetic)