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Re: IEEE inexact-flag not working on the Alpha (despite -mieee-with-inexact)?
- From: Roberto Bagnara <bagnara at cs dot unipr dot it>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: gcc at gcc dot gnu dot org, "The Parma Polyhedra Library developers' list" <ppl-devel at cs dot unipr dot it>
- Date: Thu, 18 Sep 2008 15:11:54 +0200
- Subject: Re: IEEE inexact-flag not working on the Alpha (despite -mieee-with-inexact)?
- References: <48D23D14.2030006@cs.unipr.it> <jek5d9hcz1.fsf@sykes.suse.de>
Andreas Schwab wrote:
Roberto Bagnara <bagnara@cs.unipr.it> writes:
$ cat sf.cc
#include <fenv.h>
#include <cstdio>
int main() {
float x = 2;
float y = 3;
feclearexcept(FE_INEXACT);
x = x / y;
printf("%d %.1000g\n", fetestexcept(FE_INEXACT) != 0, x);
You need to enable the FENV_ACCESS pragma (which is not yet implemented)
to get defined behaviour.
Hi Andreas,
thanks for your message. Do you mean that we need to enable the FENV_ACCESS
pragma to get defined behavior only on the Alpha or also elsewhere?
Moreover, do you mean that the FENV_ACCESS pragma is unimplemented for
the Alpha or unimplemented everywhere?
I am asking these questions because we observe this behavior only on the Alpha:
on all the other platforms we tested things seem to work fine. However, your
words could be interpreted as saying that, today, with GCC there is no way
to use feclearexcept() and fetestexcept() and get defined behavior.
Thanks again,
Roberto
--
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara@cs.unipr.it