[gmx-users] intel compiler + amd64: help needed.

[David van der Spoel]

Jones de Andrade wrote:
> Hi all!
> 
> Ok, got what should be done. But now I have a (big) question: this code 
> compiles properly with gcc. Ok, maybe that means difference of tolerance 
> between different compilers. But the code also compiles with intel on 
> intel machines, and seems to work properly on older amd machines (not 
> quite sure if they need to be so old that there is no SSE even).
> 
> Is there any possibility the compiler is messing out with us somehow? 
> Cause the same machine, different compilers, would mean bogus or 
> something comiler, but same compiler, differente machines (or different 
> cpu manufacturer?), seems to mean evil economics practices. :(
> 
> Is there any chance this "suppositions" could be right? And so, it would 
> be useless to try to crack our heads on "debugging" for one specific 
> compiler the more optimized code of the world?
> 
> Thanks for everything in advance.

There may be a problem with arguments passing. The vararg mechanism is a 
sleezy way of passing an arbitrary number of arguments to a function. It 
is based on macros, and since arguments are passed as either ints, 
doubles or strings, where ints may be 4 bytes and the others 8 bytes 
there could be confusion in the compiler. We could probably make it 
fool-proof, try attached file just for fun.


> 
> Jones
> 
> On 5/31/06, *David Mathog* <mathog at caltech.edu 
> <mailto:mathog at caltech.edu>> wrote:
> 
>      > Program received signal SIGSEGV, Segmentation fault.
>      > 0x00002aaaab15a88c in __find_specmb () from /lib64/tls/libc.so.6
>      > (gdb) where
>      > #0  0x00002aaaab15a88c in __find_specmb () from /lib64/tls/libc.so.6
>      > #1  0x00002aaaab140e6f in vfprintf () from /lib64/tls/libc.so.6
>      > #2  0x00002aaaab15e2a9 in vsprintf () from /lib64/tls/libc.so.6
>      > #3  0x00002aaaab149568 in sprintf () from /lib64/tls/libc.so.6
>      > #4  0x000000000040248b in mknb_code (format=0x40cd2e "s") at
>      > mknb_metacode.c:282
> 
>     This says that there's a call to sprintf() at mknb_metacode.c line
>     282.  Just before that call check all the parameters that will
>     be passed to sprintf.  You can do that in the debugger, but you
>     might find it easier to just put a bunch of printf's in at that point.
>     Looks like there's a a bad pointer in there somewhere.  Once you
>     figure out which variable is bogus trace back up through the following
>     code with the debugger (or more printf's)
> 
>      > #5  0x0000000000401aaf in mknb_declare_real (name=0x7fffffffd0d0
>      > "ix1,iy1,iz1,fix1,fiy1,fiz1") at mknb_metacode.c:104
>      > #6  0x0000000000403e62 in mknb_declare_variables () at
>      > mknb_declarations.c:258
>      > #7  0x0000000000400fef in mknb_write_function () at mknb.c:154
>      > #8  0x00000000004017cf in main (argc=1, argv=0x7fffffffd628) at
>     mknb.c:348
> 
>     until you find out where things have gone wrong.
> 
>     Regards,
> 
> 
>     David Mathog
>     mathog at caltech.edu <mailto:mathog at caltech.edu>
>     Manager, Sequence Analysis Facility, Biology Division, Caltech
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> gmx-users mailing list    gmx-users at gromacs.org
> http://www.gromacs.org/mailman/listinfo/gmx-users
> Please don't post (un)subscribe requests to the list. Use the 
> www interface or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/mailing_lists/users.php


-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: mknb_metacode.c
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20060531/bef0ba15/attachment.c>