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Re: bug report:
From: |
Kevin Ryde |
Subject: |
Re: bug report: |
Date: |
29 Jun 2001 09:48:58 +1000 |
User-agent: |
Gnus/5.0808 (Gnus v5.8.8) Emacs/20.5 |
Jean-Christophe Filliatre <address@hidden> writes:
>
> I think I've found a bug of mpz_fdiv_q. The file bug.c is attached
> below. Here is the bug report:
>
> ======================================================================
> GMP version number: 3.1.1
>
> test program: bug.c
>
> compilation: gcc -c -I. bug.c .libs/libgmp.a
>
> what is wrong: execution crashes on a floating point exception
Is this a divide by zero? You could put it under gdb and do a stack
backtrace with "where" if you like. You could check "b" isn't zero
for some strange reason too.
If the backtrace is uninformative you could try a build with just
CFLAGS=-g to avoid -fomit-frame-pointer (and hope very hard the
problem still arises).
> Configuration options:
> ./configure --prefix=/usr
>
> gcc -v:
> Reading specs from /usr/lib/gcc-lib/i686-pc-linux-gnu/pgcc-2.91.66/specs
> gcc version pgcc-2.91.66 19990314 (egcs-1.1.2 release)
>
> uname -a:
> Linux gemini 2.2.13-7mdk #1 Wed Sep 15 18:02:18 CEST 1999 i686 unknown
>
> ./config.guess:
> pentium2-pc-linux-gnu
I don't think I've got that compiler handy. Is it the pentium hacked
gcc from a while ago (or maybe I'm thinking of something else)?
> ======================================================================
>
> I noticed that bug doesn't reproduce on another of my machines, where
> we have:
>
> ======================================================================
> gcc -v:
> Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/egcs-2.91.66/specs
> gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
>
> uname -a:
> Linux pc803 2.2.17 #2 Thu Sep 21 16:18:38 MEST 2000 i686 unknown
>
> ./config.guess:
> pentium3-pc-linux-gnu
> ======================================================================
>
> So I guess it is related to specialized assembly code for Celeron
> processors.
The differences between pentium2 and pentium3 are minimal, so it's
perhaps more likely to be the compiler.
> (This bug is quite annoying for me, so I would appreciate a patch if
> you can provide one easily.)
You can build on p3 for p2,
./configure --target=pentium2-pc-linux-gnu
The only differences currently are the mpn_popcount and mpn_hamdist
implementations, so in fact for the test program the p3 build should
run already.
- bug report:, Jean-Christophe Filliatre, 2001/06/25
- Re: bug report:,
Kevin Ryde <=