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Re: gnu fortran compiler on 64 bit machines
- From: Tim Prince <tprince at computer dot org>
- To: zuheyr <alsalihi at vki dot ac dot be>
- Cc: fortran at gcc dot gnu dot org
- Date: Tue, 02 Oct 2007 05:50:11 -0700
- Subject: Re: gnu fortran compiler on 64 bit machines
- References: <12996731.post@talk.nabble.com>
zuheyr wrote:
> Hello,
>
> I am using GNU fortran on 32/64 bit Fedora Core 6 Linux machines using
> Pentium IV and AMD
> Athlon processors. I use fortran 77 and fortran 90.
>
..
> However, most notably there are also big differences between gnu fortran
> compiled codes on 32 and 64 bit machines.
> The 64 bit code does not at all run on what 32 bit gnu compiled code runs.
>
> In the compilations I used the simplest -O flag but there are differences
> even with -g flag.
Besides checking for uninitialized variables, range errors, etc.
consider using similar options if you want the 32 and 64 bit results to
be similar, such as -march=pentium4 -mfpmath=sse Remember that the 32-
and 64-bit defaults are different.