Index: gcc/fortran/trans-expr.c
===================================================================
*** gcc/fortran/trans-expr.c	(revision 117052)
--- gcc/fortran/trans-expr.c	(working copy)
*************** gfc_conv_function_call (gfc_se * se, gfc
*** 2029,2035 ****
  	  gfc_add_expr_to_block (&se->pre, tmp);
  	}
  
!       if (fsym && fsym->ts.type == BT_CHARACTER
  	     && parmse.string_length == NULL_TREE
  	     && e->ts.type == BT_PROCEDURE
  	     && e->symtree->n.sym->ts.type == BT_CHARACTER
--- 2029,2035 ----
  	  gfc_add_expr_to_block (&se->pre, tmp);
  	}
  
!       if (e && fsym && fsym->ts.type == BT_CHARACTER
  	     && parmse.string_length == NULL_TREE
  	     && e->ts.type == BT_PROCEDURE
  	     && e->symtree->n.sym->ts.type == BT_CHARACTER
Index: gcc/testsuite/gfortran.dg/optional_assumed_charlen_1.f90
===================================================================
*** gcc/testsuite/gfortran.dg/optional_assumed_charlen_1.f90	(revision 0)
--- gcc/testsuite/gfortran.dg/optional_assumed_charlen_1.f90	(revision 0)
***************
*** 0 ****
--- 1,20 ----
+ ! { dg-do compile }
+ ! Tests the fix for PR29284 in which an ICE would occur in converting
+ ! the call to a suboutine with an assumed character length, optional
+ ! dummy that is not present.
+ !
+ ! Contributed by Rakuen Himawari  <rakuen_himawari@yahoo.co.jp>
+ !
+       MODULE foo
+       CONTAINS
+         SUBROUTINE sub1(a)
+           CHARACTER (LEN=*), OPTIONAL :: a
+           WRITE(*,*) 'foo bar'
+         END SUBROUTINE sub1
+ 
+       SUBROUTINE sub2
+         CALL sub1()
+       END SUBROUTINE sub2
+ 
+      END MODULE foo
+ ! { dg-final { cleanup-modules "foo" } }