ENH: Use f90 compiler specified in f2py command line args for pgi compiler - #16730

Won't this do the wrong thing when an f77 compiler is requested?

It would call the pgf90 executable rather than the pgfortran executable.
Those are actually the same compiler according to the PGI Fortran Reference Guide (https://www.pgroup.com/resources/docs/20.4/openpower/fortran-ref-guide/index.htm):

pgf90, pgf95, and pgfortran are the same compiler that has evolved from Fortran 90 to Fortran 2003 standards. The older names are supported so that makefiles that were written using pgf90/pgf95, will still work. All three names refer to the same one compiler that supports the Fortran 2003 language standard.

What about old compiler versions which do not have an f90 compiler at all? Maybe we already do not support those.

It won't neither have the pgfortran executable as this one is newer than the pgf90 executable.
IMO the question should be raised the other way around: what about newer code, fortran 95 code or fortran 2003 code for instance? It would be compiled with the pgf90 executable instead of the pgfortran executable. It would work because those are the same, but it's confusing.

Nevertheless, the command line utility lets the user dial in his compiler command of choice, I feel like the system should use the specified command for linking as well. This is where I may be mistaking.

@eric-wieser Are you OK with this?

@eric-wieser Ping.

I'd like to put this. If there are problems we can address them when they arise. @danbeibei Could you make a release note in doc/release/upcoming_changes, look at the other entries and the README to see how it is done. Also, what happens if the --f90exec is not part of the command?

OK, I added a release note.

If the --f90exec option is not provided the pgf90 executable is used instead of the pgfortran one.
This brings us back to the previous considerations.

@charris: I don't know nearly enough about building fortran to have an opinion here, my question above was to prompt opinions from people who might.

@eric-wieser Neither do I :) In these cases we need to depend on people who actually use the relevant compiler for fixes that make things work for them.

Thanks @danbeibei .