[gcc r13-7986] Fortran: Set hidden string length for pointer components [PR67740].

[gcc r13-7986] Fortran: Set hidden string length for pointer components [PR67740].

[Paul Thomas]

https://gcc.gnu.org/g:6fb12d3a0456a3503a670d95803aef10549f0134

commit r13-7986-g6fb12d3a0456a3503a670d95803aef10549f0134
Author: Paul Thomas <pault@gcc.gnu.org>
Date:   Thu Oct 12 07:26:59 2023 +0100

    Fortran: Set hidden string length for pointer components [PR67740].
    
    2023-10-11  Paul Thomas  <pault@gcc.gnu.org>
    
    gcc/fortran
            PR fortran/67740
            * trans-expr.cc (gfc_trans_pointer_assignment): Set the hidden
            string length component for pointer assignment to character
            pointer components.
    
    gcc/testsuite/
            PR fortran/67740
            * gfortran.dg/pr67740.f90: New test
    
    (cherry picked from commit 701363d827d45d3e3601735fa42f95644fda8b64)

Diff:
---
 gcc/fortran/trans-expr.cc             | 33 +++++++++++++++++++++++++++++----
 gcc/testsuite/gfortran.dg/pr67740.f90 | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index da1fa3143783..ae35c01a9e0f 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -10213,11 +10213,36 @@ 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));
diff --git a/gcc/testsuite/gfortran.dg/pr67740.f90 b/gcc/testsuite/gfortran.dg/pr67740.f90
new file mode 100644
index 000000000000..bf70ff223632
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr67740.f90
@@ -0,0 +1,32 @@
+! { 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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