[Patch, fortran] PR67740 - Wrong association status of allocatable character pointer in derived types

[Paul Richard Thomas <paul.richard.thomas@gmail.com>]

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Hi All,

The title line of the PR should have been changed a long time since. As
noted in comment 5, the original problem was fixed in 10.5.

This patch fixes the problem described in comments 4 and 6, where the
hidden string length component was not being set in pointer assignment of
character arrays.

The fix regtests. OK for trunk and 13-branch?

Thanks are due to Harald for bringing this to my attention.

Paul

Fortran: Set hidden string length for pointer components [PR67440]

2023-10-11  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
PR fortran/pr67740
* trans-expr.cc (gfc_trans_pointer_assignment): Set the hidden
string length component for pointer assignment to character
pointer components.

gcc/testsuite/
PR fortran/87477
* gfortran.dg/pr67740.f90: New test

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! {dg-do compile }
! { dg-options "-fdump-tree-original" }
!
! Check the fix for the testcase in comment 4, where the hidden string length
! component of the array pointer component was not set.
!
! Contributed by Sebastien Bardeau  <bardeau@iram.fr>
!
program test2
  implicit none
  character(len=10), allocatable, target :: s(:)
  character(len=:),  pointer             :: sptr(:)
  type :: pointer_typec0_t
    character(len=:), pointer :: data0
    character(len=:), pointer :: data1(:)
  end type pointer_typec0_t
  type(pointer_typec0_t) :: co
  !
  allocate(s(3))
  s(1) = '1234567890'
  s(2) = 'qwertyuio '
  s(3) = 'asdfghjk  '
  !
  sptr => s
  co%data0 => s(1)
  co%data1 => s
  !
  if (any (sptr .ne. s)) stop 1
  if (co%data0 .ne. s(1)) stop 2
  if (any (co%data1 .ne. s)) stop 3 ! Hidden string length was not set
end program test2
! { dg-final { scan-tree-dump-times "co._data1_length = 10;" 1 "original" } }

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diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 860b73c4968..7beefa2e69c 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -10403,11 +10403,36 @@ gfc_trans_pointer_assignment (gfc_expr * expr1, gfc_expr * expr2)
 	}
 
       if (expr1->ts.type == BT_CHARACTER
-	  && expr1->symtree->n.sym->ts.deferred
-	  && expr1->symtree->n.sym->ts.u.cl->backend_decl
-	  && VAR_P (expr1->symtree->n.sym->ts.u.cl->backend_decl))
+	  && expr1->ts.deferred)
 	{
-	  tmp = expr1->symtree->n.sym->ts.u.cl->backend_decl;
+	  gfc_symbol *psym = expr1->symtree->n.sym;
+	  tmp = NULL_TREE;
+	  if (psym->ts.type == BT_CHARACTER)
+	    {
+	      gcc_assert (psym->ts.u.cl->backend_decl
+			  && VAR_P (psym->ts.u.cl->backend_decl));
+	      tmp = psym->ts.u.cl->backend_decl;
+	    }
+	  else if (expr1->ts.u.cl->backend_decl
+		   && VAR_P (expr1->ts.u.cl->backend_decl))
+	    tmp = expr1->ts.u.cl->backend_decl;
+	  else if (TREE_CODE (lse.expr) == COMPONENT_REF)
+	    {
+	      gfc_ref *ref = expr1->ref;
+	      for (;ref; ref = ref->next)
+		{
+		  if (ref->type == REF_COMPONENT
+		      && ref->u.c.component->ts.type == BT_CHARACTER
+		      && gfc_deferred_strlen (ref->u.c.component, &tmp))
+		    tmp = fold_build3_loc (input_location, COMPONENT_REF,
+					   TREE_TYPE (tmp),
+					   TREE_OPERAND (lse.expr, 0),
+					   tmp, NULL_TREE);
+		}
+	    }
+
+	  gcc_assert (tmp);
+
 	  if (expr2->expr_type != EXPR_NULL)
 	    gfc_add_modify (&block, tmp,
 			    fold_convert (TREE_TYPE (tmp), strlen_rhs));