Re: c/8395: gcc 2.95.4 and 3.2 generate wrong code for double on intel

[Tim Prince <tprince@computer.org>]

The following reply was made to PR c/8395; it has been noted by GNATS.

From: Tim Prince <tprince@computer.org>
To: Marco Bernardo <bernardo@sti.uniurb.it>,
	Bruce Allen <ballen@gravity.phys.uwm.edu>
Cc: Bruce Allen <ballen@aei.mpg.de>, <gcc-gnats@gcc.gnu.org>,
	<gcc-prs@gcc.gnu.org>, <gcc-bugs@gcc.gnu.org>, <nobody@gcc.gnu.org>
Subject: Re: c/8395: gcc 2.95.4 and 3.2 generate wrong code for double on intel
Date: Sat, 2 Nov 2002 08:15:47 -0800

 On Saturday 02 November 2002 07:42, Marco Bernardo wrote:
 
 > Let me conclude by saying that my intention is not to be polemic.
 > My point of view is that of a university professor who wants to teach
 > to his students that there is a great alternative to Microsoft,
 > which is Linux and the free software world.
 > You would then understand that it is very difficult for me to support gcc
 > and to teach my students how to use gcc in the presence of such a strange
 > behavior, which is not justifiable at all on a scientific basis.
 >
 >
 From a professorial point of view, you should be encouraging your students to 
 consult expert references on floating point numerics, even if you don't care 
 to do so yourself.  Before you start arguing about IEEE standards and 
 scientific bases, you should be reading up on them, and the technical reasons 
 for including the extended precision option.
 If you are teaching at this level of detail, you could show your students how 
 to set 53-bit rounding mode in order to duplicate the fpu settings of 
 Microsoft compilers, how to use fpu mode settings to test code reliability, 
 and how to break the Microsoft compiler by putting the fpu in standard 
 default mode.  As standard C does not define a function for this purpose, the 
 C committee must not have considered it to be as large an issue as you.
 -- 
 Tim Prince