re PR fortran/71203 (ICE in add_init_expr_to_sym, at fortran/decl.c:1512 and :1564)

2019-03-06  Harald Anlauf  <anlauf@gmx.de>

	PR fortran/71203
	* expr.c (simplify_const_ref): Avoid null pointer dereference.

	PR fortran/71203
	* gfortran.dg/substr_8.f90: New test.

From-SVN: r269444

gcc/fortran/ChangeLog

+2019-03-06  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/71203
+	* expr.c (simplify_const_ref): Avoid null pointer dereference.
+
 2019-03-03  Harald Anlauf  <anlauf@gmx.de>
 	    Steven G. Kargl  <kargl@gcc.gnu.org>
 

gcc/fortran/expr.c

@@ -1897,8 +1897,14 @@ simplify_const_ref (gfc_expr *p)
 			string_len = 0;
 
 		      if (!p->ts.u.cl)
-			p->ts.u.cl = gfc_new_charlen (p->symtree->n.sym->ns,
-						      NULL);
+			{
+			  if (p->symtree)
+			    p->ts.u.cl = gfc_new_charlen (p->symtree->n.sym->ns,
+							  NULL);
+			  else
+			    p->ts.u.cl = gfc_new_charlen (gfc_current_ns,
+							  NULL);
+			}
 		      else
 			gfc_free_expr (p->ts.u.cl->length);
 

gcc/testsuite/ChangeLog

+2019-03-06  Harald Anlauf  <anlauf@gmx.de>
+
+	PR fortran/71203
+	* gfortran.dg/substr_8.f90: New test.
+
 2019-03-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/87148

gcc/testsuite/gfortran.dg/substr_8.f90

+! { dg-do run }
+! PR fortran/71203 - used to ICE on zero-length arrays or substrings
+! Derived from original test cases by Gerhard Steinmetz
+
+program p
+  implicit none
+  character(3), parameter :: a(4) = ' '
+  character(*), parameter :: b(4) = 'abc'
+  character(*), parameter :: x(*) = a(2:2)(3:1)
+  character(*), parameter :: y(*) = a(2:1)(3:1)
+  character(*), parameter :: z(*) = b(2:1)(2:3)
+  if (size (x) /= 1 .or. len(x) /= 0) stop 1
+  if (size (y) /= 0 .or. len(y) /= 0) stop 2
+  if (size (z) /= 0 .or. len(z) /= 2) stop 3
+end