[gmx-developers] GROMACS 3.1.x and 3.2.x AltiVec support fix

Charlie Peck charliep at cs.earlham.edu
Thu May 6 07:03:57 CEST 2004

At 2:42 AM +0200 5/6/04, Erik Lindahl wrote:
>Hi Charlie,
>Thanks for finding this. Just to make sure - this is a vanilla gcc, 
>and not the motorola-patched version? (Yellow Dog used to distribute 
>a motorola patch for gcc-2.95 before gcc had Altivec support, but I 
>think it's the vanilla version now).

c0$ gcc -v
Reading specs from /usr/local/lib/gcc-lib/powerpc-unknown-linux-gnu/3.3.2/specs
Configured with: ./configure --enable-threads --with-cpu=powerpc 
Thread model: posix
gcc version 3.3.2

I'm pretty sure they are using the "plain" FSF distribution now.  I
seem to remember one with the Motorola patch saying so in the output
of gcc -v.

>The problem is that the OS X compiler is also "gcc" but the version 
>distributed by Apple doesn't use any altivec.h file (it isn't even 

There are a couple of threads about this at simdtech.org, it sounds
like Apple is working on merging the changes from the FSF codeline
but it goes slowly.

>Oh well, I guess I can see if there are any vendor predefined Macros 
>on OS X that aren't defined by the FSF version of gcc, or I can 
>search for an altivec.h file during the configure phase...

A configure test that just does "#include <altivec.h>" and a main()
should be all that's needed.


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