> -freal-4-real-8 is not equivalent to -fdefault-real-8 and -fdefault-double-8.
>
> -freal-4-real-8 interprets any 4-byte real type, whether it is a
> default real type or explicitly declared as 4-byte, as a 8-byte double
> precision type, and that applies to all variables, functions and
> constants.
>
> -fdefault-real-8 will promote only default real type to double
> precision and only variables and functions. Since constants are
> usually declared explicitly as 4-byte, e.g. 1.01223e0 is an explicitly
> defined 4-byte constant in gfortran, they will not be promoted.
I agree with the above and I think this should go into the manual. One
thing which can be done with -fdefault-real-8, but not with
-freal-4-real-8 is to work around some pitfalls of these otions by
specifying explicit kinds when needed (this probably explains why less
tests fail with the former option than with the later, see results at the
end of this mail).
In my opinion, these options, while useful, have several pitfalls:
(1) call to external procedures (especially in libraries),
(2) alignements in EQUIVALENCE and/or COMMON,
(3) generic interfaces,
(4) BOZ,
(5) I/Os,
(6) ...
I wonder if they should not have their own page in the manual with a big
warning at the beginning telling the user that these options are likely to
break "legacy" codes.
The raw test results are the following
make -k check-gfortran
RUNTESTFLAGS="--target_board=unix'{-m32/-finteger-4-integer-8,
-m64/-finteger-4-integer-8,-m32/-freal-4-real-8,-m64/-freal-4-real-8,-m32/-freal-8-real-10,-m64/-freal-8-real-10}'"
=== gfortran Summary for unix/-m32/-finteger-4-integer-8 ===
# of expected passes 37336
# of unexpected failures 896
# of expected failures 39
# of unresolved testcases 1
# of unsupported tests 570
=== gfortran Summary for unix/-m64/-finteger-4-integer-8 ===
# of expected passes 37728
# of unexpected failures 840
# of expected failures 39
# of unsupported tests 409
=== gfortran Summary for unix/-m32/-freal-4-real-8 ===
# of expected passes 37526
# of unexpected failures 702
# of expected failures 39
# of unsupported tests 570
=== gfortran Summary for unix/-m64/-freal-4-real-8 ===
# of expected passes 37857
# of unexpected failures 698
# of expected failures 39
# of unsupported tests 409
=== gfortran Summary for unix/-m32/-freal-8-real-10 ===
# of expected passes 37928
# of unexpected failures 394
# of expected failures 39
# of untested testcases 8
# of unsupported tests 570
=== gfortran Summary for unix/-m64/-freal-8-real-10 ===
# of expected passes 38300
# of unexpected failures 357
# of expected failures 39
# of untested testcases 8
# of unsupported tests 409
=== gfortran Summary ===
# of expected passes 226675
# of unexpected failures 3887
# of expected failures 234
# of unresolved testcases 1
# of untested testcases 16
# of unsupported tests 2937
to be compared with
make -k check-gfortran
RUNTESTFLAGS="--target_board=unix'{-m32/-fdefault-integer-8,
-m64/-fdefault-integer-8,-m32/-fdefault-real-8,-m64/-fdefault-real-8}'"
=== gfortran Summary for unix/-m32/-fdefault-integer-8 ===
# of expected passes 37794
# of unexpected failures 489
# of expected failures 39
# of unresolved testcases 24
# of unsupported tests 570
=== gfortran Summary for unix/-m64/-fdefault-integer-8 ===
# of expected passes 38111
# of unexpected failures 499
# of expected failures 39
# of unresolved testcases 24
# of unsupported tests 409
=== gfortran Summary for unix/-m32/-fdefault-real-8 ===
# of expected passes 37705
# of unexpected failures 539
# of expected failures 39
# of untested testcases 8
# of unsupported tests 570
=== gfortran Summary for unix/-m64/-fdefault-real-8 ===
# of expected passes 38028
# of unexpected failures 535
# of expected failures 39
# of untested testcases 8
# of unsupported tests 409
=== gfortran Summary ===
# of expected passes 151638
# of unexpected failures 2062
# of expected failures 156
# of unresolved testcases 48
# of untested testcases 16
# of unsupported tests 1958
I did not have the time to look in detail to the results. From a quick
glance I can tell that there are overlaps between the failures of
-fdefault-*-8 and -f*-4-*-8. In particular the ICEs with coarray appear
for both cases (I have open pr51682).
Dominique
