https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615
--- Comment #6 from Ben Barrowes <barrowes at alum dot mit.edu> --- 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.
