@@ -2336,6 +2336,7 @@ typedef struct
gfc_expr *io_unit, *format_expr, *rec, *advance, *iostat, *size, *iomsg,
*id, *pos, *asynchronous, *blank, *decimal, *delim, *pad, *round,
*sign, *extra_comma, *dt_io_kind, *udtio;
+ char default_exp;
gfc_symbol *namelist;
/* A format_label of `format_asterisk' indicates the "*" format */
@@ -1471,6 +1471,7 @@ compatibility extensions along with those enabled by @option{-std=legacy}.
* .XOR. operator::
* Bitwise logical operators::
* Extended I/O specifiers::
+* Default exponents::
@end menu
@node Old-style kind specifications
@@ -2696,6 +2697,15 @@ supported on other systems.
@end table
+@node Default exponents
+@subsection Default exponents
+@cindex exponent
+
+For compatibility, GNU Fortran supports a default exponent of zero in real
+constants with @option{-fdec}. For example, @code{9e} would be
+interpreted as @code{9e0}, rather than an error.
+
+
@node Extensions not implemented in GNU Fortran
@section Extensions not implemented in GNU Fortran
@cindex extensions, not implemented
@@ -4163,6 +4163,10 @@ get_io_list:
goto syntax;
}
+ /* See if we want to use defaults for missing exponents in real transfers. */
+ if (flag_dec)
+ dt->default_exp = 1;
+
/* A full IO statement has been matched. Check the constraints. spec_end is
supplied for cases where no locus is supplied. */
m = check_io_constraints (k, dt, io_code, &spec_end);
@@ -118,4 +118,5 @@ IOPARM (dt, round, 1 << 23, char2)
IOPARM (dt, sign, 1 << 24, char1)
#define IOPARM_dt_f2003 (1 << 25)
#define IOPARM_dt_dtio (1 << 26)
+#define IOPARM_dt_default_exp (1 << 27)
IOPARM (dt, u, 0, pad)
@@ -483,7 +483,7 @@ backup:
static match
match_real_constant (gfc_expr **result, int signflag)
{
- int kind, count, seen_dp, seen_digits, is_iso_c;
+ int kind, count, seen_dp, seen_digits, is_iso_c, default_exponent;
locus old_loc, temp_loc;
char *p, *buffer, c, exp_char;
gfc_expr *e;
@@ -494,6 +494,7 @@ match_real_constant (gfc_expr **result, int signflag)
e = NULL;
+ default_exponent = 0;
count = 0;
seen_dp = 0;
seen_digits = 0;
@@ -575,8 +576,14 @@ match_real_constant (gfc_expr **result, int signflag)
if (!ISDIGIT (c))
{
- gfc_error ("Missing exponent in real number at %C");
- return MATCH_ERROR;
+ /* With -fdec, default exponent to 0 instead of complaining. */
+ if (flag_dec)
+ default_exponent = 1;
+ else
+ {
+ gfc_error ("Missing exponent in real number at %C");
+ return MATCH_ERROR;
+ }
}
while (ISDIGIT (c))
@@ -597,8 +604,8 @@ done:
gfc_current_locus = old_loc;
gfc_gobble_whitespace ();
- buffer = (char *) alloca (count + 1);
- memset (buffer, '\0', count + 1);
+ buffer = (char *) alloca (count + default_exponent + 1);
+ memset (buffer, '\0', count + default_exponent + 1);
p = buffer;
c = gfc_next_ascii_char ();
@@ -621,6 +628,8 @@ done:
c = gfc_next_ascii_char ();
}
+ if (default_exponent)
+ *p++ = '0';
kind = get_kind (&is_iso_c);
if (kind == -1)
@@ -1911,6 +1911,9 @@ build_dt (tree function, gfc_code * code)
if (dt->udtio)
mask |= IOPARM_dt_dtio;
+ if (dt->default_exp)
+ mask |= IOPARM_dt_default_exp;
+
if (dt->namelist)
{
if (dt->format_expr || dt->format_label)
new file mode 100644
@@ -0,0 +1,35 @@
+! { dg-do run }
+! { dg-options "-fdec" }
+!
+! Test support for providing a default exponent of zero when unspecified in
+! real constants with -fdec.
+!
+
+subroutine asserteq (rexp, ract, msg)
+ real, intent(in) :: rexp, ract
+ character(*), intent(in) :: msg
+ if (rexp .ne. ract) then
+ write (*, '(A,F12.6,F12.6)') msg, rexp, ract
+ call abort()
+ endif
+end subroutine
+
+implicit none
+
+real, parameter :: r1 = 8e0
+real, parameter :: r2 = 8e ! { equivalent to 8e0 }
+real, volatile :: r3, r4
+character(2) :: s
+r3 = 8e ! { equivalent to 8e0 }
+s = '8e'
+
+read (s, *) r4
+
+call asserteq (r1, r2, "[const]")
+call asserteq (r1, r3, "[vol. ]")
+call asserteq (r1, r4, "[read ]")
+
+r4 = 8e + 48e
+call asserteq (56e, r4, "[sum ]")
+
+end
new file mode 100644
@@ -0,0 +1,13 @@
+! { dg-do compile }
+! { dg-options "" }
+!
+! Make sure we still see an error for missing exponents without -fdec.
+!
+
+implicit none
+
+real, parameter :: r1 = 8e ! { dg-error "Missing exponent" }
+real, volatile :: r2
+r2 = 8e ! { dg-error "Missing exponent" }
+
+end
new file mode 100644
@@ -0,0 +1,15 @@
+! { dg-do run "xfail *-*-*" }
+! { dg-options "" }
+!
+! Make sure we still see an error for missing exponents without -fdec.
+!
+
+implicit none
+
+real :: r
+character(2) :: s
+s = '8e'
+
+read (s, *) r ! { XFAIL "Bad real number" }
+
+end
@@ -443,6 +443,7 @@ st_parameter_inquire;
#define IOPARM_DT_HAS_SIGN (1 << 24)
#define IOPARM_DT_HAS_F2003 (1 << 25)
#define IOPARM_DT_HAS_UDTIO (1 << 26)
+#define IOPARM_DT_DEFAULT_EXP (1 << 27)
/* Internal use bit. */
#define IOPARM_DT_IONML_SET (1u << 31)
@@ -1374,7 +1374,16 @@ parse_real (st_parameter_dt *dtp, void *buffer, int length)
exp2:
if (!isdigit (c))
- goto bad_exponent;
+ {
+ /* Extension: allow default exponent of 0 when omitted. */
+ if (dtp->common.flags & IOPARM_DT_DEFAULT_EXP)
+ {
+ push_char (dtp, '0');
+ goto done;
+ }
+ else
+ goto bad_exponent;
+ }
push_char (dtp, c);
@@ -1816,7 +1825,16 @@ read_real (st_parameter_dt *dtp, void * dest, int length)
exp2:
if (!isdigit (c))
- goto bad_exponent;
+ {
+ /* Extension: allow default exponent of 0 when omitted. */
+ if (dtp->common.flags & IOPARM_DT_DEFAULT_EXP)
+ {
+ push_char (dtp, '0');
+ goto done;
+ }
+ else
+ goto bad_exponent;
+ }
push_char (dtp, c);
@@ -1087,7 +1087,13 @@ exponent:
the d parameter before explict conversion takes place. */
if (w == 0)
- goto bad_float;
+ {
+ /* Extension: allow default exponent of 0 when omitted. */
+ if (dtp->common.flags & IOPARM_DT_DEFAULT_EXP)
+ goto done;
+ else
+ goto bad_float;
+ }
if (dtp->u.p.blank_status == BLANK_UNSPECIFIED)
{
All, Attached is a patch to the GNU Fortran front-end and runtime library (libgfortran) which accepts real numbers with missing exponents as if '0' was given as the exponent when the compile flag -fdec is given, for further compatibility with legacy compilers. By default, GNU Fortran will reject real constants such as '9e' or '15.2e'. With the patch and -fdec, such numbers are accepted and treated as '9e0' (9) or '15.2e0' (15.2), both at compile-time through the front-end and at runtime through libgfortran. For compile-time this is trivial. For runtime, An IOPARM_DT flag bit is added to the usual flags to track whether a program was compiled with the "default exponent" behavior, which the library can detect at runtime for programs individually. No space is required in the st_parameter_dt structure, and the behavior should be backwards-compatible (by design of the IOPARM structures/flags). Bootstraps and regtests on x86_64-redhat-linux. OK for trunk? --- Fritz Reese From: Fritz Reese <fritzoreese@gmail.com> Date: Wed, 5 Oct 2016 18:27:56 -0400 Subject: [PATCH] Default missing exponents to 0 with -fdec. gcc/fortran/ * gfortran.texi: Document. * gfortran.h (gfc_dt): New field default_exp. * primary.c (match_real_constant): Default exponent with -fdec. * io.c (match_io): Set dt.default_exp with -fdec. * ioparm.def (IOPARM_dt_default_exp): New. * trans-io.c (build_dt): Set IOPARM_dt_default_exp with -fdec. libgfortran/io/ * io.h (IOPARM_DT_DEFAULT_EXP): New flag bit. * list_read.c (parse_real, read_real): Allow omission of exponent with IOPARM_DT_DEFAULT_EXP. * read.c (read_f): Ditto. gcc/testsuite/gfortran.dg/ * dec_exp_1.f90, dec_exp_2.f90, dec_exp_3.f90: New testcases. --- gcc/fortran/gfortran.h | 1 + gcc/fortran/gfortran.texi | 10 ++++++++ gcc/fortran/io.c | 4 +++ gcc/fortran/ioparm.def | 1 + gcc/fortran/primary.c | 19 ++++++++++++---- gcc/fortran/trans-io.c | 3 ++ gcc/testsuite/gfortran.dg/dec_exp_1.f90 | 35 +++++++++++++++++++++++++++++++ gcc/testsuite/gfortran.dg/dec_exp_2.f90 | 13 +++++++++++ gcc/testsuite/gfortran.dg/dec_exp_3.f90 | 15 +++++++++++++ libgfortran/io/io.h | 1 + libgfortran/io/list_read.c | 22 +++++++++++++++++- libgfortran/io/read.c | 8 ++++++- 12 files changed, 124 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/dec_exp_1.f90 create mode 100644 gcc/testsuite/gfortran.dg/dec_exp_2.f90 create mode 100644 gcc/testsuite/gfortran.dg/dec_exp_3.f90