Fortran: restrictions on integer arguments to SYSTEM_CLOCK [PR112609]

Fortran 2023 added restrictions on integer arguments to SYSTEM_CLOCK to
have a decimal exponent range at least as large as a default integer,
and that all integer arguments have the same kind type parameter.

gcc/fortran/ChangeLog:

	PR fortran/112609
	* check.cc (gfc_check_system_clock): Add checks on integer arguments
	to SYSTEM_CLOCK specific to F2023.
	* error.cc (notify_std_msg): Adjust to handle new features added
	in F2023.
	* gfortran.texi (_gfortran_set_options): Document GFC_STD_F2023_DEL,
	remove obsolete option GFC_STD_F2008_TS and fix enumeration values.
	* libgfortran.h (GFC_STD_F2023_DEL): Add and use in GFC_STD_OPT_F23.
	* options.cc (set_default_std_flags): Add GFC_STD_F2023_DEL.

gcc/testsuite/ChangeLog:

	PR fortran/112609
	* gfortran.dg/system_clock_1.f90: Add option -std=f2003.
	* gfortran.dg/system_clock_3.f08: Add option -std=f2008.
	* gfortran.dg/system_clock_4.f90: New test.

8 files changed, 95 insertions, 10 deletions

diff --git a/gcc/fortran/check.cc b/gcc/fortran/check.cc
index 6c45e65..3b1a0f9 100644
--- a/gcc/fortran/check.cc
+++ b/gcc/fortran/check.cc
@@ -6774,6 +6774,8 @@ bool
 gfc_check_system_clock (gfc_expr *count, gfc_expr *count_rate,
 			gfc_expr *count_max)
 {
+  int first_int_kind = -1;
+
   if (count != NULL)
     {
       if (!scalar_check (count, 0))
@@ -6788,8 +6790,17 @@ gfc_check_system_clock (gfc_expr *count, gfc_expr *count_rate,
 			      &count->where))
 	return false;
 
+      if (count->ts.kind < gfc_default_integer_kind
+	  && !gfc_notify_std (GFC_STD_F2023_DEL,
+			      "COUNT argument to SYSTEM_CLOCK at %L "
+			      "with kind smaller than default integer",
+			      &count->where))
+	return false;
+
       if (!variable_check (count, 0, false))
 	return false;
+
+      first_int_kind = count->ts.kind;
     }
 
   if (count_rate != NULL)
@@ -6816,6 +6827,16 @@ gfc_check_system_clock (gfc_expr *count, gfc_expr *count_rate,
 				  "SYSTEM_CLOCK at %L has non-default kind",
 				  &count_rate->where))
 	    return false;
+
+	  if (count_rate->ts.kind < gfc_default_integer_kind
+	      && !gfc_notify_std (GFC_STD_F2023_DEL,
+				  "COUNT_RATE argument to SYSTEM_CLOCK at %L "
+				  "with kind smaller than default integer",
+				  &count_rate->where))
+	    return false;
+
+	  if (first_int_kind < 0)
+	    first_int_kind = count_rate->ts.kind;
 	}
 
     }
@@ -6836,6 +6857,35 @@ gfc_check_system_clock (gfc_expr *count, gfc_expr *count_rate,
 
       if (!variable_check (count_max, 2, false))
 	return false;
+
+      if (count_max->ts.kind < gfc_default_integer_kind
+	  && !gfc_notify_std (GFC_STD_F2023_DEL,
+			      "COUNT_MAX argument to SYSTEM_CLOCK at %L "
+			      "with kind smaller than default integer",
+			      &count_max->where))
+	return false;
+
+      if (first_int_kind < 0)
+	first_int_kind = count_max->ts.kind;
+    }
+
+  if (first_int_kind > 0)
+    {
+      if (count_rate
+	  && count_rate->ts.type == BT_INTEGER
+	  && count_rate->ts.kind != first_int_kind
+	  && !gfc_notify_std (GFC_STD_F2023_DEL,
+			      "integer arguments to SYSTEM_CLOCK at %L "
+			      "with different kind parameters",
+			      &count_rate->where))
+	return false;
+
+      if (count_max && count_max->ts.kind != first_int_kind
+	  && !gfc_notify_std (GFC_STD_F2023_DEL,
+			      "integer arguments to SYSTEM_CLOCK at %L "
+			      "with different kind parameters",
+			      &count_max->where))
+	return false;
     }
 
   return true;
diff --git a/gcc/fortran/error.cc b/gcc/fortran/error.cc
index 2ac51e9..56d2e636 100644
--- a/gcc/fortran/error.cc
+++ b/gcc/fortran/error.cc
@@ -980,7 +980,11 @@ char const*
 notify_std_msg(int std)
 {
 
-  if (std & GFC_STD_F2018_DEL)
+  if (std & GFC_STD_F2023_DEL)
+    return _("Prohibited in Fortran 2023:");
+  else if (std & GFC_STD_F2023)
+    return _("Fortran 2023:");
+  else if (std & GFC_STD_F2018_DEL)
     return _("Fortran 2018 deleted feature:");
   else if (std & GFC_STD_F2018_OBS)
     return _("Fortran 2018 obsolescent feature:");
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index 41857cc..c29cb78 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -3476,13 +3476,13 @@ standard.  Possible values are (bitwise or-ed) @code{GFC_STD_F77} (1),
 @code{GFC_STD_F95_OBS} (2), @code{GFC_STD_F95_DEL} (4),
 @code{GFC_STD_F95} (8), @code{GFC_STD_F2003} (16), @code{GFC_STD_GNU}
 (32), @code{GFC_STD_LEGACY} (64), @code{GFC_STD_F2008} (128),
-@code{GFC_STD_F2008_OBS} (256), @code{GFC_STD_F2008_TS} (512),
-@code{GFC_STD_F2018} (1024), @code{GFC_STD_F2018_OBS} (2048),
-@code{GFC_STD=F2018_DEL} (4096), and @code{GFC_STD=F2023} (8192).
+@code{GFC_STD_F2008_OBS} (256), @code{GFC_STD_F2018} (512),
+@code{GFC_STD_F2018_OBS} (1024), @code{GFC_STD_F2018_DEL} (2048),
+@code{GFC_STD_F2023} (4096), and @code{GFC_STD_F2023_DEL} (8192).
 Default: @code{GFC_STD_F95_OBS | GFC_STD_F95_DEL | GFC_STD_F95 |
-GFC_STD_F2003 | GFC_STD_F2008 | GFC_STD_F2008_TS | GFC_STD_F2008_OBS
+GFC_STD_F2003 | GFC_STD_F2008 | GFC_STD_F2008_OBS
 | GFC_STD_F77 | GFC_STD_F2018 | GFC_STD_F2018_OBS | GFC_STD_F2018_DEL
-| GFC_STD_F2023 | GFC_STD_GNU | GFC_STD_LEGACY}.
+| GFC_STD_F2023 | GFC_STD_F2023_DEL | GFC_STD_GNU | GFC_STD_LEGACY}.
 @item @var{option}[1] @tab Standard-warning flag; prints a warning to
 standard error.  Default: @code{GFC_STD_F95_DEL | GFC_STD_LEGACY}.
 @item @var{option}[2] @tab If non zero, enable pedantic checking.
diff --git a/gcc/fortran/libgfortran.h b/gcc/fortran/libgfortran.h
index bdddb31..2c71b90 100644
--- a/gcc/fortran/libgfortran.h
+++ b/gcc/fortran/libgfortran.h
@@ -20,8 +20,10 @@ along with GCC; see the file COPYING3.  If not see
 
 /* Flags to specify which standard/extension contains a feature.
    Note that no features were obsoleted nor deleted in F2003 nor in F2023.
+   Nevertheless, some features available in F2018 are prohibited in F2023.
    Please remember to keep those definitions in sync with
    gfortran.texi.  */
+#define GFC_STD_F2023_DEL	(1<<13)	/* Prohibited in F2023.  */
 #define GFC_STD_F2023		(1<<12)	/* New in F2023.  */
 #define GFC_STD_F2018_DEL	(1<<11)	/* Deleted in F2018.  */
 #define GFC_STD_F2018_OBS	(1<<10)	/* Obsolescent in F2018.  */
@@ -41,12 +43,13 @@ along with GCC; see the file COPYING3.  If not see
  * are allowed with a certain -std option.  */
 #define GFC_STD_OPT_F95		(GFC_STD_F77 | GFC_STD_F95 | GFC_STD_F95_OBS  \
 				| GFC_STD_F2008_OBS | GFC_STD_F2018_OBS \
-				| GFC_STD_F2018_DEL)
+				| GFC_STD_F2018_DEL | GFC_STD_F2023_DEL)
 #define GFC_STD_OPT_F03		(GFC_STD_OPT_F95 | GFC_STD_F2003)
 #define GFC_STD_OPT_F08		(GFC_STD_OPT_F03 | GFC_STD_F2008)
 #define GFC_STD_OPT_F18		((GFC_STD_OPT_F08 | GFC_STD_F2018) \
 				& (~GFC_STD_F2018_DEL))
-#define GFC_STD_OPT_F23		(GFC_STD_OPT_F18 | GFC_STD_F2023)
+#define GFC_STD_OPT_F23		((GFC_STD_OPT_F18 | GFC_STD_F2023) \
+				& (~GFC_STD_F2023_DEL))
 
 /* 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.  */
diff --git a/gcc/fortran/options.cc b/gcc/fortran/options.cc
index b788521..02a29f8 100644
--- a/gcc/fortran/options.cc
+++ b/gcc/fortran/options.cc
@@ -57,8 +57,10 @@ set_default_std_flags (void)
   gfc_option.allow_std = GFC_STD_F95_OBS | GFC_STD_F95_DEL
     | GFC_STD_F2003 | GFC_STD_F2008 | GFC_STD_F95 | GFC_STD_F77
     | GFC_STD_F2008_OBS | GFC_STD_GNU | GFC_STD_LEGACY
-    | GFC_STD_F2018 | GFC_STD_F2018_DEL | GFC_STD_F2018_OBS | GFC_STD_F2023;
-  gfc_option.warn_std = GFC_STD_F2018_DEL | GFC_STD_F95_DEL | GFC_STD_LEGACY;
+    | GFC_STD_F2018 | GFC_STD_F2018_DEL | GFC_STD_F2018_OBS | GFC_STD_F2023
+    | GFC_STD_F2023_DEL;
+  gfc_option.warn_std = GFC_STD_F2018_DEL | GFC_STD_F95_DEL | GFC_STD_LEGACY
+    | GFC_STD_F2023_DEL;
 }
 
 /* Set (or unset) the DEC extension flags.  */
diff --git a/gcc/testsuite/gfortran.dg/system_clock_1.f90 b/gcc/testsuite/gfortran.dg/system_clock_1.f90
index 41027de..0cb0145 100644
--- a/gcc/testsuite/gfortran.dg/system_clock_1.f90
+++ b/gcc/testsuite/gfortran.dg/system_clock_1.f90
@@ -1,4 +1,5 @@
 ! { dg-do run }
+! { dg-options "-std=f2003" }
 
   integer :: i, j, k
   integer(kind=8) :: i8, j8, k8
diff --git a/gcc/testsuite/gfortran.dg/system_clock_3.f08 b/gcc/testsuite/gfortran.dg/system_clock_3.f08
index e52a51a..c12849b 100644
--- a/gcc/testsuite/gfortran.dg/system_clock_3.f08
+++ b/gcc/testsuite/gfortran.dg/system_clock_3.f08
@@ -1,4 +1,5 @@
 ! { dg-do run }
+! { dg-options "-std=f2008" }
 ! PR64432
 program countem
   implicit none
diff --git a/gcc/testsuite/gfortran.dg/system_clock_4.f90 b/gcc/testsuite/gfortran.dg/system_clock_4.f90
new file mode 100644
index 0000000..1bb42ef
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/system_clock_4.f90
@@ -0,0 +1,24 @@
+! { dg-do compile }
+! { dg-options "-std=f2023" }
+! PR fortran/112609 - F2023 restrictions on integer arguments to SYSTEM_CLOCK
+
+program p
+  implicit none
+  integer    :: i,  j,  k
+  integer(2) :: i2, j2, k2
+  integer(8) :: i8, j8, k8
+  real       :: x
+
+  call system_clock(count=i2)      ! { dg-error "kind smaller than default integer" }
+  call system_clock(count_rate=j2) ! { dg-error "kind smaller than default integer" }
+  call system_clock(count_max=k2)  ! { dg-error "kind smaller than default integer" }
+
+  call system_clock(count=i8,count_rate=x,count_max=k8)
+  call system_clock(count=i, count_rate=j8)     ! { dg-error "different kind" }
+  call system_clock(count=i8,count_rate=j)      ! { dg-error "different kind" }
+  call system_clock(count=i, count_max=k8)      ! { dg-error "different kind" }
+  call system_clock(count=i8,count_max=k)       ! { dg-error "different kind" }
+  call system_clock(count_rate=j, count_max=k8) ! { dg-error "different kind" }
+  call system_clock(count_rate=j8,count_max=k)  ! { dg-error "different kind" }
+  call system_clock(i,x,k8)                     ! { dg-error "different kind" }
+end