https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84382
--- Comment #6 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Fri, Apr 05, 2019 at 11:15:30PM +0000, sgk at troutmask dot
apl.washington.edu wrote:
>
> We could add
>
> #define GFC_STD_OPT_GNU03 (GFC_STD_OPT_F03 | GFC_STD_GNU)
> #define GFC_STD_OPT_GNU08 (GFC_STD_OPT_F08 | GFC_STD_GNU)
> #define GFC_STD_OPT_GNU18 (GFC_STD_OPT_F18 | GFC_STD_GNU)
>
Against my better judgment.
%cat a.f90
program foo
integer :: i = z'1234' ! Nonstandard initialization
print *, i
end program foo
% gfcx -o z a.f90 && ./z
4660
% gfcx -o z -std=f2003 a.f90 && ./z
a.f90:2:17:
2 | integer :: i = z'1234' ! Nonstandard initialization
| 1
Error: GNU Extension: BOZ literal at (1) outside a DATA statement and outside
INT/REAL/DBLE/CMPLX
% gfcx -o z -std=gnu2003 a.f90 && ./z
4660
Index: gcc/fortran/libgfortran.h
===================================================================
--- gcc/fortran/libgfortran.h (revision 270181)
+++ gcc/fortran/libgfortran.h (working copy)
@@ -46,6 +46,10 @@ along with GCC; see the file COPYING3. If not see
#define GFC_STD_OPT_F18 ((GFC_STD_OPT_F08 | GFC_STD_F2018) \
& (~GFC_STD_F2018_DEL))
+#define GFC_STD_OPT_GNU03 (GFC_STD_OPT_F03 | GFC_STD_GNU)
+#define GFC_STD_OPT_GNU08 (GFC_STD_OPT_F08 | GFC_STD_GNU)
+#define GFC_STD_OPT_GNU18 (GFC_STD_OPT_F18 | GFC_STD_GNU)
+
/* Bitmasks for the various FPE that can be enabled. These need to be
straight integers
e.g., 8 instead of (1<<3), because they will be included in Fortran source.
*/
#define GFC_FPE_INVALID 1
Index: gcc/fortran/lang.opt
===================================================================
--- gcc/fortran/lang.opt (revision 270181)
+++ gcc/fortran/lang.opt (working copy)
@@ -826,6 +826,18 @@ std=gnu
Fortran
Conform to nothing in particular.
+std=gnu2003
+Fortran
+Conform to the ISO Fortran 2003 standard with GNU Fortran extensions.
+
+std=gnu2008
+Fortran
+Conform to the ISO Fortran 2008 standard with GNU Fortran extensions.
+
+std=gnu2018
+Fortran
+Conform to the ISO Fortran 2018 standard with GNU Fortran extensions.
+
std=legacy
Fortran
Accept extensions to support legacy code.
Index: gcc/fortran/options.c
===================================================================
--- gcc/fortran/options.c (revision 270181)
+++ gcc/fortran/options.c (working copy)
@@ -778,6 +778,31 @@ gfc_handle_option (size_t scode, const char *arg, HOST
set_default_std_flags ();
break;
+ case OPT_std_gnu2003:
+ gfc_option.allow_std = GFC_STD_OPT_GNU03;
+ gfc_option.warn_std = GFC_STD_F95_OBS;
+ gfc_option.max_identifier_length = 63;
+ warn_ampersand = 1;
+ warn_tabs = 1;
+ break;
+
+ case OPT_std_gnu2008:
+ gfc_option.allow_std = GFC_STD_OPT_GNU08;
+ gfc_option.warn_std = GFC_STD_F95_OBS | GFC_STD_F2008_OBS;
+ gfc_option.max_identifier_length = 63;
+ warn_ampersand = 1;
+ warn_tabs = 1;
+ break;
+
+ case OPT_std_gnu2018:
+ gfc_option.allow_std = GFC_STD_OPT_GNU18;
+ gfc_option.warn_std = GFC_STD_F95_OBS | GFC_STD_F2008_OBS
+ | GFC_STD_F2018_OBS;
+ gfc_option.max_identifier_length = 63;
+ warn_ampersand = 1;
+ warn_tabs = 1;
+ break;
+
case OPT_std_legacy:
set_default_std_flags ();
gfc_option.warn_std = 0;
Index: gcc/fortran/invoke.texi
===================================================================
--- gcc/fortran/invoke.texi (revision 270181)
+++ gcc/fortran/invoke.texi (working copy)
@@ -492,23 +492,28 @@ representation of the translated Fortran code, produce
@item -std=@var{std}
@opindex @code{std=}@var{std} option
-Specify the standard to which the program is expected to conform,
-which may be one of @samp{f95}, @samp{f2003}, @samp{f2008},
-@samp{f2018}, @samp{gnu}, or @samp{legacy}. The default value for
-@var{std} is @samp{gnu}, which specifies a superset of the latest
-Fortran standard that includes all of the extensions supported by GNU
-Fortran, although warnings will be given for obsolete extensions not
+Specify the standard to which the program is expected to conform
+which may be one of @samp{f95}, @samp{f2003}, @samp{f2008}, @samp{f2018},
+@samp{gnu}, @samp{gnu2003}, @samp{gnu2008}, @samp{gnu2018},or @samp{legacy}.
+The default value for @var{std} is @samp{gnu}, which specifies a superset
+of the latest Fortran standard that includes all of the extensions supported
+by GNU Fortran, although warnings will be given for obsolete extensions not
recommended for use in new code. The @samp{legacy} value is
equivalent but without the warnings for obsolete extensions, and may
-be useful for old non-standard programs. The @samp{f95},
+be useful for old nonstandard programs. The @samp{f95},
@samp{f2003}, @samp{f2008}, and @samp{f2018} values specify strict
conformance to the Fortran 95, Fortran 2003, Fortran 2008 and Fortran
2018 standards, respectively; errors are given for all extensions
beyond the relevant language standard, and warnings are given for the
Fortran 77 features that are permitted but obsolescent in later
-standards. The deprecated option @samp{-std=f2008ts} acts as an alias for
+standards. The deprecated option @samp{-std=f2008ts} acts as an alias for
@samp{-std=f2018}. It is only present for backwards compatibility with
earlier gfortran versions and should not be used any more.
+The @samp{gnu2003}, @samp{gnu2008}, and @samp{gnu2018} values specify
+adherences to the Fortran 2003, Fortran 2008 and Fortran
+2018 standards; while allowing GNU Fortran extensions. For example,
+@code{std=gnu2003} would reject Fortran 2008 and 2018 feature, but
+would allow nonstandard construction such as @code{REAL*4}.
@item -ftest-forall-temp
@opindex @code{ftest-forall-temp}
