James A. Peltier jpeltier at
Thu May 22 18:53:53 CEST 2008

On Thu, 22 May 2008, Torbjorn Granlund wrote:

> You don't spell it out, but it seems you're configuring for a 64-bit
> x86 processor.
> The enable-fat function is only for 32-bit x86.  There are plans to move it also
> to 64-bit x86, but that will not happen for a few more months.
> (There should perhaps be a neater error message about this.)
> -- 
> Torbjörn

Yes, you are indeed correct.  I am compiling on a AMD64 machine and wanted 
to ensure that Intel X64 machines could have an optimized compiler as 
well, since it appears to me that --enable-fat build a binary with all 
"supported" extensions in it.  That way if it was running on AMD it would 
use AMD instruction sets but if on Intel it would use Intel instruction 

That said, since fat binaries are not supported on x86_64 CPUs, what is 
the best way to compile x86_64 binaries.  What is the best lowest common 
denominator, setting --build and --host to x86_64-unknown-linux-gnu or 

James A. Peltier
Systems Analyst (FASNet), VIVARIUM Technical Director
Simon Fraser University - Burnaby Campus
Phone   : 778-782-6573
Fax     : 778-782-3045
Mobile  : 778-840-6434
E-Mail  : jpeltier at
Website : |
MSN     : subatomic_spam at

More information about the gmp-bugs mailing list