Treat form feed as whitespace.

	gcc/fortran/
	* gfortran.texi: Document.
	* gfortran.h (gfc_is_whitespace): Include form feed ('\f').

	gcc/testsuite/gfortran.dg/
	* feed_1.f90, feed_2.f90: New testcases.

From-SVN: r241517

gcc/fortran/ChangeLog

 2016-10-25  Fritz Reese <fritzoreese@gmail.com>
 
+	* gfortran.texi: Document.
+	* gfortran.h (gfc_is_whitespace): Include form feed ('\f').
+
+2016-10-25  Fritz Reese <fritzoreese@gmail.com>
+
 	* invoke.texi, gfortran.texi: Touch up documentation of -fdec.
 	* gfortran.h (gfc_option): Move flag_dec_structure out of gfc_option.
 	* decl.c (match_record_decl, gfc_match_decl_type_spec,
@@ -10,6 +15,7 @@
 	* lang.opt (fdec): Use Fortran Var to create flag_dec.
 	* options.c (set_dec_flags): With -fdec enable -fcray-pointer,
 	-fd-lines-as-comments (default), -fdollar-ok, and legacy std flags.
+
 2016-10-24  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR fortran/77828

gcc/fortran/gfortran.h

@@ -60,7 +60,7 @@ not after.
 #define MAX_SUBRECORD_LENGTH 2147483639   /* 2**31-9 */
 
 
-#define gfc_is_whitespace(c) ((c==' ') || (c=='\t'))
+#define gfc_is_whitespace(c) ((c==' ') || (c=='\t') || (c=='\f'))
 
 /* Macros to check for groups of structure-like types and flavors since
    derived types, structures, maps, unions are often treated similarly. */

gcc/fortran/gfortran.texi

@@ -1465,6 +1465,7 @@ compatibility extensions along with those enabled by @option{-std=legacy}.
 * Type variants for integer intrinsics::
 * AUTOMATIC and STATIC attributes::
 * Extended math intrinsics::
+* Form feed as whitespace::
 @end menu
 
 @node Old-style kind specifications
@@ -2510,6 +2511,16 @@ and then multiplying it by a constant radian-to-degree (or degree-to-radian)
 factor, as appropriate. The factor is computed at compile-time as 180/pi (or
 pi/180).
 
+@node Form feed as whitespace
+@subsection Form feed as whitespace
+@cindex form feed whitespace
+
+Historically, legacy compilers allowed insertion of form feed characters ('\f',
+ASCII 0xC) at the beginning of lines for formatted output to line printers,
+though the Fortran standard does not mention this. GNU Fortran supports the
+interpretation of form feed characters in source as whitespace for
+compatibility.
+
 
 @node Extensions not implemented in GNU Fortran
 @section Extensions not implemented in GNU Fortran

gcc/testsuite/ChangeLog

+2016-10-25  Fritz Reese <fritzoreese@gmail.com>
+
+	gfortran.dg/
+	* feed_1.f90, feed_2.f90: New testcases.
+
 2016-10-25  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/78106

gcc/testsuite/gfortran.dg/feed_1.f90

+! { dg-do compile }
+! { dg-options "-ffree-form" }
+! Test acceptance of form feed character in free source.
+
+implicit none
+integer, volatile :: x
+
+
+
+x = 5
+
+end

gcc/testsuite/gfortran.dg/feed_2.f90

+      ! { dg-do compile }
+      ! { dg-options "-ffixed-form" }
+      ! Test acceptance of form feed character in fixed source.
+
+      implicit none
+      integer, volatile :: x
+
+
+
+      x = 5
+
+      end