[Bug fortran/81615] New: save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

Bug ID: 81615
   Summary: save-temps and gfortran produces *.f90 files instead
of *.i or *i90 files
   Product: gcc
   Version: unknown
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: fortran
  Assignee: unassigned at gcc dot gnu.org
  Reporter: barrowes at alum dot mit.edu
  Target Milestone: ---

If I have a file test1.f:

  program test2
  real x
  x=3.0
C#ifdef DDD
C  x=2.0
C#endif
  print *,'x=',x
  end

and I compile it with:

gfortran -save-temps -o test0 test0.f

I get two temporary files, test0.o and test0.s.

If I uncomment the directive:

  program test2
  real x
  x=3.0
#ifdef MPI
  x=2.0
#endif
  print *,'x=',x
  end

and compile with:

gfortran -cpp -save-temps -o test0 test0.f

In addition to the two temporary files above, a test0.f90 is produced that
looks like:

# 1 "test0.f"
# 1 ""
# 1 ""
# 1 "test0.f"
  program test2
  real x
  x=3.0
  print *,'x=',x
  end


I was under the impression that I would get a test0.i file since the only
documentation of using -save-temps I can find comes from the gcc docs:
https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html#index-save-temps
which mentions *.i files in their example.


And if I have a file test1.f90:

program test1
real x
x=3.0
#ifdef MPI
x=2.0
#endif
print *,'x=',x
end

and I compile with:

gfortran -cpp -save-temps -o test1 test1.f90

The test1.o and test1.s files are produced, but no preprocessed fortran source
file is produced (I suppose because the source file already has the f90
extension).

How can I get a preprocessed source file in this case? Where is this behavior
of -save-temps producing *.f90 files documented? Can I change the f90 extension
of the preprocessed temporary files to i or i90 instead of f90?

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #2 from Ben Barrowes  ---
Then how does one get a preprocessed/savetemp file from an existing *.f90 file?

In the case of C, preprocessed and temp files have different extensions and are
thus easily identified after compiling. For gfortran,
preprocessing/saveingtemps of *.f files produces *.f90 files which is
confusing, and preprocessing/savetemps of *.f90 files produces no output.

Gfortran needs to produce preprocessed/savetemps that have unique and easily
identifiable extensions. If not *.i and *.i90, then something else like *.t and
*.t90 or similar.

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #4 from Ben Barrowes  ---
It has been a while.

Is there any way to save the temporary preprocessed files in gfortran?

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #6 from Ben Barrowes  ---
There are many cases where people do not use a capital "F", but still have
preprocessor directives in the code. In these cases, no proprocessed file is
written out right now, AFAIK.

So perhaps as you suggest we could add a new suffix to the old filename. Then
test1.f would become test.f.i and test1.f90 would also become test1.f.i, etc.
Having this one rule would be a concise solution and have a guaranteed output
in all cases.

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #8 from Ben Barrowes  ---
Maybe *.fpp ?

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #10 from Ben Barrowes  ---
The reason the stdout redirection doesn't work for me is because I want to save
these preprocessed files during a "make" session. When I make, thousands of
fotran files are preprocessed and compiled. How do I save the stdout from each
one into its own directory?

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #12 from Ben Barrowes  ---
I use these intermediate files during the software analysis process, but then
delete them later. They are useful for me to have.

When I am given a makefile, it is often 1000's loc. I am not sure I want to go
in and modify it such as you suggest below and tell the customer it is for
their own good. I'd rather be able to set a couple of switches to the
preprocessor and get what I want.

gfortran already allows to create a *.d file in each directory for each file.
Is that poor software design as well? And when gfortran files are preprocessed
all into a *.f90 file, except when they are not (see Thomas's email below), is
that poor software design?

ifort allows for the creation of these intermediate preprocessed files,
creating *.i and *.i90 files.

IBM XL allows this as well using the -d switch:
https://www.ibm.com/docs/en/xl-fortran-aix/16.1.0?topic=preprocessor-passing-fortran-files-through-c
And the intermediate filename becomes Ffilename.f*

Can gfortran be modified to have the option to do this as well?

[Bug fortran/81615] save-temps and gfortran produces *.f90 files instead of *.i or *i90 files

[barrowes at alum dot mit.edu via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615

--- Comment #14 from Ben Barrowes  ---
Thanks for engaging, and thanks for the suggestion. I might be able to do this
over the winter. Could you give me a hint as to where to look. Which files.