[gcc r16-8035] Fortran: gfortran PDT component access [PR97818]

[Paul Thomas]

https://gcc.gnu.org/g:9ff20883d44ef568805a4a8f731977e77a1c9459

commit r16-8035-g9ff20883d44ef568805a4a8f731977e77a1c9459
Author: Paul Thomas <pault@gcc.gnu.org>
Date:   Thu Mar 12 11:21:23 2026 +0000

    Fortran: gfortran PDT component access [PR97818]
    
    2026-03-12  Paul Thomas  <pault@gcc.gnu.org>
    
    gcc/fortran
            PR fortran/97818
            * trans-decl.cc (gfc_trans_deferred_vars): Make sure that the
            result symbol is referenced before allocating parameterized
            components.
    
    gcc/testsuite/
            PR fortran/97818
            * gfortran.dg/pdt_88.f03: New test.

Diff:
---
 gcc/fortran/trans-decl.cc            |  1 +
 gcc/testsuite/gfortran.dg/pdt_88.f03 | 78 ++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 4dfb390e4ebb..8649d0fbc819 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -4910,6 +4910,7 @@ gfc_trans_deferred_vars (gfc_symbol * proc_sym, gfc_wrapped_block * block)
 	 && proc_sym != proc_sym->result) ? proc_sym->result : NULL;
 
   if (sym && !sym->attr.allocatable && !sym->attr.pointer
+      && sym->attr.referenced
       && IS_PDT (sym) && !gfc_has_default_initializer (sym->ts.u.derived))
     {
       gfc_init_block (&tmpblock);
diff --git a/gcc/testsuite/gfortran.dg/pdt_88.f03 b/gcc/testsuite/gfortran.dg/pdt_88.f03
new file mode 100644
index 000000000000..31bc2e827f8f
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pdt_88.f03
@@ -0,0 +1,78 @@
+! { dg-do compile }
+!
+! Test the fix for pr97818. Used to ICE in structure_alloc_comps, at
+! fortran/trans-array.cc:10211 because the parameterized function results
+! had not been set.
+!
+! Contributed by Adam Jermyn  <adamjermyn@gmail.com>
+!
+module my_type_module
+   
+   implicit none
+      private
+   public :: my_type, &
+      assignment(=), &
+      operator(+)
+
+   type :: my_type(n)
+      integer, len :: n ! Length of array of independent variables
+      real :: val
+      real :: d1
+      real :: d2
+      real :: d1Array(n)
+      real :: d1_d2
+      real :: d1_d1Array(n)
+      real :: d2_d1Array(n)
+      real :: d1_d2_d1Array(n)
+   end type my_type
+   
+   interface assignment(=)
+      module procedure assign_from_self
+   end interface assignment(=)
+   
+   interface operator(+)
+      module procedure add_self
+      module procedure add_self_real
+   end interface operator(+)
+   
+   
+   contains
+
+   subroutine assign_from_self(this, other)
+      type(my_type(n=*)), intent(inout) :: this
+      type(my_type(n=this%n)), intent(in) :: other
+   end subroutine assign_from_self
+
+   function add_self(x, y) result(binary)
+      type(my_type(n=*)), intent(in) :: x
+      type(my_type(n=*)), intent(in) :: y
+      type(my_type(n=x%n)) :: binary
+   end function add_self
+   
+   function add_self_real(x, y) result(unary)
+      type(my_type(n=*)), intent(in) :: x
+      real, intent(in) :: y
+      type(my_type(n=x%n)) :: unary
+   end function add_self_real
+
+end module my_type_module
+
+
+program test_auto_diff
+   use my_type_module
+
+   call do_test_auto_diff_2var_order3_dArray(5)
+
+   contains
+
+   subroutine do_test_auto_diff_2var_order3_dArray(n)
+      integer, intent(in) :: n
+      type(my_type(n=n)) :: x, y, z
+
+      z = (x + 2.0) + ((x + 2.0) + 1.0)
+
+   end subroutine do_test_auto_diff_2var_order3_dArray
+
+
+
+end program test_auto_diff