[Bug fortran/84594] Warning: Use of the NUMERIC_STORAGE_SIZE named constant from intrinsic module ISO_FORTRAN_ENV at (1) is incompatible with option -fdefault-integer-8

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84594

--- Comment #2 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> This is expected.

Indeed! I have found it in module.c.

> This PR should be closed as INVALID.

(1) AFAICT this not documented. Is NUMERIC_STORAGE_SIZE the only parameter in
ISO_FORTRAN_ENV triggering a warning?

(2) The warning is not emitted with -fdefault-real-10 nor with
-fdefault-real-16. I guess this was overlooked when these options were added.

(3) The options -finteger-4-integer-8 and -freal-*-real-* don't trigger the
warning. Is it because they change all the occurrences of INT or REAL, while
-fdefault-* only change the implicit ones?

(4) I stumbled on this warning while running the test suite with
-fdefault-integer-8 and I'ls like to decrease the noise by using one of the
following:

(a) add an ONLY clause;

(b) add a dg-prune-output;

(c) add a filter in gcc/testsuite/lib/prune.exp;

(d) do (c) in my working trees.