gfortran 4.1 patches...

[FX Coudert]

Ante-scriptum: one day, I'll get fed up and stop replying to private  
email sent to me that would be better suited for the list... but  
until then, I will patiently forward this mail to the list and ask  
people kindly *not* *to* *send* *private* *mail* *for* *enquiries*  
*about* *collaborative* *projects*. Thanks!

> Dear Dr. Coudert,
>   I sent an e-mail similar to this one to the gfortan listserv  
> yesterday, and didn't quite get the response I was looking for.  I  
> was wondering if you could help me.

If you know the answer you're looking for, what is the question worth?

> The build fails due to a lack of lshift_ in gfortran. I am guessing  
> that it will find further problems with other missing fortran  
> intrinsics.

lshift is an extension to the Fortran standard. It's not strictly a  
"fortran intrinsic".

>   After researching the problem, I am aware that our best bet is to  
> upgrade gcc to 4.2 or newer.  While I don't have a problem with  
> doing this, we share our clusters with another research group, and  
> they cannot afford the down-time needed to test the new gcc (plus,  
> they are generally scared by the word "upgrade").  Thus, I would  
> like to try to implement the patches you have given at this url  
> (http://gcc.gnu.org/ml/fortran/2006-07/msg00397.html).
>
>   I am aware that a newer version of gcc is the best fix for the  
> problem, but we use fortran so infrequently (all of our active  
> programming is done in c,c++, and ruby) that I think this quick fix  
> may be worth trying.

My advice is to either edit the source to use ISHFT (think automated  
source modifications), which is standard Fortran and is the same as  
LSHIFT (as is explained in the documentation at http://gcc.gnu.org/ 
onlinedocs/gfortran/LSHIFT.html), or create your own small library  
with a single ishft function that calls LSHIFT internally.

>   Could you give me some hints/instructions as to how to implement  
> these? Is there any existing documentation for the Fortran- 
> illiterate like me? Any help is greatly appreciated.


What you need is not to be Fortran-literate. What you need is to be  
literate about building source code with the GNU tools (autoconf, make).

To be short, to build a patched compiler: get the source from your  
vendor (RedHat), get the build instructions from them (RPM spec file,  
I suppose, is found in the source RPM), apply the patches you've  
found to the sources, then proceed with building the compiler.

FX

-- 
François-Xavier Coudert
http://www.homepages.ucl.ac.uk/~uccafco/