[PATCH fortran] Use fold_build everywhere

[Tobias Schlüter]

FX Coudert wrote:
>> Attached is an updated version of the patch which also modifies the 
>> copyright years of the touched files and which fixes a typo I made 
>> when I tried to fix formatting in the diff.
> 
> My understanding was that the copyright years in the files need to 
> include year X iff a release of the codebase is done in year X, 
> independently of whether the file was actually modified or not. From 
> http://www.gnu.org/prep/maintain/html_node/Copyright-Notices.html:
>> To update the list of year numbers, add each year in which you have 
>> made nontrivial changes to the package. (Here we assume you're using a 
>> publicly accessible revision control server, so that every revision 
>> installed is also immediately and automatically published.) When you 
>> add the new year, it is not required to keep track which files have 
>> seen significant changes in the new year and which have not. It is 
>> recommended and simpler to add the new year to all files in the 
>> package, and be done with it for the rest of the year.

Well, that doesn't make wrong what I did :-)  Certainly it's better than 
not updating the numbers at all.  I will take care of the rest later today.

> 
> Other than that, the patch is OK. To satisfy my curiosity: I sometimes 
> used buildN() instead of fold_buildN() when I know that the expression 
> can't be simplified, to avoid extra burden on the middle-end, was that 
> wrong or is it just that the benefit is too small to notice?

Last I checked the optimizers eat practically all the time in a 
compilation, so it's not important time-wise.  Note that (at least 
according to my understanding) fold_* would more appropriately be called 
canonicalize_*, i.e. not only does it fold trees with constant 
arguments, it also puts trees into standard forms by replacing 
expressions with equivalent ones (say, something like (!a && !b) -> !(a 
|| b)).  Therefore, folding may have benefits even for non-constant 
arguments.

Thanks,
- Tobi