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Re: Performance analysis of Polyhedron/gas_dyn

From: Robert Dewar <dewar at adacore dot com>
To: Geert Bosch <bosch at adacore dot com>
Cc: Janne Blomqvist <blomqvist dot janne at gmail dot com>, Richard Guenther <richard dot guenther at gmail dot com>, gfortran <fortran at gcc dot gnu dot org>, gcc at gcc dot gnu dot org
Date: Fri, 27 Apr 2007 10:50:32 -0400
Subject: Re: Performance analysis of Polyhedron/gas_dyn
References: <4631A891.5020002@gmail.com> <84fc9c000704270127s4eb0030p9d27fd5fdff73cf8@mail.gmail.com> <4631CCAA.3010403@gmail.com> <B6A68967-62DF-4623-B0B8-1403304E586A@adacore.com>

Geert Bosch wrote:

I truly doubt that any of the compilers you mention use these
instructions without NR iteration to get required precision.


If they do then they are probably seriously broken, not just
because they give complete junk results in this case, but
such an implementation would indicate a complete lack of
knowledge of how to do fpt reasonably. As Geert says, this
instruction is intended ONLY as part of an NR implementation.

References:
- Re: Performance analysis of Polyhedron/gas_dyn
  - From: Richard Guenther
- Re: Performance analysis of Polyhedron/gas_dyn
  - From: Janne Blomqvist
- Re: Performance analysis of Polyhedron/gas_dyn
  - From: Geert Bosch

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