[Fortran] PR 92072 – fix %C corner case

        PR fortran/92072
        * error.c (error_print, gfc_format_decoder): Fix %C column-
        offset handling.

From-SVN: r276953

gcc/fortran/ChangeLog

+2019-10-14  Tobias Burnus  <tobias@codesourcery.com>
+
+	PR fortran/92072
+	* error.c (error_print, gfc_format_decoder): Fix %C column-
+	offset handling.
+
 2019-10-13  Damian Rouson  <damain@sourceryinstitue.org>
 
 	PR fortran/91513
@@ -110,7 +116,8 @@
 
 2019-10-04  Tobias Burnus  <tobias@codesourcery.com>
 
-	* error (error_print, gfc_format_decoder): Fix off-by one issue with %C.
+	* error.c (error_print, gfc_format_decoder): Fix off-by one issue
+	with %C.
 
 2019-10-03  Steven G. Kargl  <kargl@gcc.gnu.org>
 

gcc/fortran/error.c

+#pragma GCC optimize("O0")
 /* Handle errors.
    Copyright (C) 2000-2019 Free Software Foundation, Inc.
    Contributed by Andy Vaught & Niels Kristian Bech Jensen
@@ -619,7 +620,7 @@ error_print (const char *type, const char *format0, va_list argp)
 		l2 = loc;
 		arg[pos].u.stringval = "(2)";
 		/* Point %C first offending character not the last good one. */
-		if (arg[pos].type == TYPE_CURRENTLOC)
+		if (arg[pos].type == TYPE_CURRENTLOC && *l2->nextc != '\0')
 		  l2->nextc++;
 	      }
 	    else
@@ -628,7 +629,7 @@ error_print (const char *type, const char *format0, va_list argp)
 		have_l1 = 1;
 		arg[pos].u.stringval = "(1)";
 		/* Point %C first offending character not the last good one. */
-		if (arg[pos].type == TYPE_CURRENTLOC)
+		if (arg[pos].type == TYPE_CURRENTLOC && *l1->nextc != '\0')
 		  l1->nextc++;
 	      }
 	    break;
@@ -969,7 +970,7 @@ gfc_format_decoder (pretty_printer *pp, text_info *text, const char *spec,
 	  loc = va_arg (*text->args_ptr, locus *);
 	gcc_assert (loc->nextc - loc->lb->line >= 0);
 	unsigned int offset = loc->nextc - loc->lb->line;
-	if (*spec == 'C')
+	if (*spec == 'C' && *loc->nextc != '\0')
 	  /* Point %C first offending character not the last good one. */
 	  offset++;
 	/* If location[0] != UNKNOWN_LOCATION means that we already