https://gcc.gnu.org/g:fb12014c4ea9967aab463524f283454ce16d9785

commit r13-10241-gfb12014c4ea9967aab463524f283454ce16d9785
Author: Paul Thomas <[email protected]>
Date:   Thu Apr 2 15:51:01 2026 +0100

    Subject: [PATCH] fortran: Preserve scalar class pointers in OpenMP 
privatization [PR120286]
    
    OpenMP privatization currently treats scalar class pointers like owned
    polymorphic class objects.  In the worker cleanup for private/firstprivate
    class pointers, the generated code finalizes and frees ptr._data even though
    the clause only copied pointer association status from a shared target.
    
    Fix this in gfc_omp_clause_copy_ctor and gfc_omp_clause_dtor by unwrapping
    saved descriptors first and by recognizing class-pointer container types
    locally in those hooks.  That keeps scalar class pointers on the
    association-only path without changing the broader polymorphic mapping
    classification used for OpenMP warnings and deep mapping.
    
    Add a runtime regression test for the original private(ptr) crash plus a
    firstprivate(ptr) association check.
    
    gcc/fortran/ChangeLog:
    
            PR fortran/120286
            * trans-openmp.cc (gfc_is_class_pointer_type): New helper.
            (gfc_omp_clause_copy_ctor): Unwrap saved descriptors before
            deciding whether privatization should preserve only pointer
            association.  Handle scalar class pointers on that path too.
            (gfc_omp_clause_dtor): Likewise.
    
    libgomp/ChangeLog:
    
            * testsuite/libgomp.fortran/pr120286.f90: New test.
    
    Signed-off-by: Christopher Albert <[email protected]>
    (cherry picked from commit 86960a3ffbd7d87b6b1d18d7cc02bf5078526bca)

Diff:
---
 gcc/fortran/trans-openmp.cc                    | 72 ++++++++++++++++++++------
 libgomp/testsuite/libgomp.fortran/pr120286.f90 | 49 ++++++++++++++++++
 2 files changed, 104 insertions(+), 17 deletions(-)

diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index d542f52761f3..8dd5903ea665 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -405,6 +405,30 @@ gfc_has_alloc_comps (tree type, tree decl)
   return false;
 }
 
+/* Return true if TYPE is a class container for a POINTER entity.  */
+
+static bool
+gfc_is_class_pointer_type (tree type)
+{
+  tree name;
+  const char *s;
+
+  if (POINTER_TYPE_P (type))
+    type = TREE_TYPE (type);
+
+  if (!GFC_CLASS_TYPE_P (type))
+    return false;
+
+  name = TYPE_NAME (type);
+  if (name && TREE_CODE (name) == TYPE_DECL)
+    name = DECL_NAME (name);
+  if (!name)
+    return false;
+
+  s = IDENTIFIER_POINTER (name);
+  return startswith (s, "__class_") && s[strlen (s) - 1] == 'p';
+}
+
 /* Return true if TYPE is polymorphic but not with pointer attribute.  */
 
 static bool
@@ -844,22 +868,29 @@ gfc_omp_clause_copy_ctor (tree clause, tree dest, tree 
src)
 {
   tree type = TREE_TYPE (dest), ptr, size, call;
   tree decl_type = TREE_TYPE (OMP_CLAUSE_DECL (clause));
+  tree orig_decl = OMP_CLAUSE_DECL (clause);
   tree cond, then_b, else_b;
   stmtblock_t block, cond_block;
 
   gcc_assert (OMP_CLAUSE_CODE (clause) == OMP_CLAUSE_FIRSTPRIVATE
              || OMP_CLAUSE_CODE (clause) == OMP_CLAUSE_LINEAR);
 
-  /* Privatize pointer, only; cf. gfc_omp_predetermined_sharing. */
-  if (DECL_P (OMP_CLAUSE_DECL (clause))
-      && GFC_DECL_ASSOCIATE_VAR_P (OMP_CLAUSE_DECL (clause)))
-    return build2 (MODIFY_EXPR, TREE_TYPE (dest), dest, src);
+  if (DECL_ARTIFICIAL (orig_decl)
+      && DECL_LANG_SPECIFIC (orig_decl)
+      && GFC_DECL_SAVED_DESCRIPTOR (orig_decl))
+    {
+      orig_decl = GFC_DECL_SAVED_DESCRIPTOR (orig_decl);
+      decl_type = TREE_TYPE (orig_decl);
+    }
 
-  if (DECL_ARTIFICIAL (OMP_CLAUSE_DECL (clause))
-      && DECL_LANG_SPECIFIC (OMP_CLAUSE_DECL (clause))
-      && GFC_DECL_SAVED_DESCRIPTOR (OMP_CLAUSE_DECL (clause)))
-    decl_type
-      = TREE_TYPE (GFC_DECL_SAVED_DESCRIPTOR (OMP_CLAUSE_DECL (clause)));
+  /* Privatize pointer association only; cf. gfc_omp_predetermined_sharing.
+     This includes scalar class pointers, whose tree type is still the class
+     record even though the Fortran entity has POINTER semantics.  */
+  if (DECL_P (orig_decl)
+      && (GFC_DECL_ASSOCIATE_VAR_P (orig_decl)
+         || GFC_DECL_GET_SCALAR_POINTER (orig_decl)
+         || gfc_is_class_pointer_type (decl_type)))
+    return build2 (MODIFY_EXPR, TREE_TYPE (dest), dest, src);
 
   if (gfc_is_polymorphic_nonptr (decl_type))
     {
@@ -1367,17 +1398,24 @@ gfc_omp_clause_dtor (tree clause, tree decl)
 {
   tree type = TREE_TYPE (decl), tem;
   tree decl_type = TREE_TYPE (OMP_CLAUSE_DECL (clause));
+  tree orig_decl = OMP_CLAUSE_DECL (clause);
+
+  if (DECL_ARTIFICIAL (orig_decl)
+      && DECL_LANG_SPECIFIC (orig_decl)
+      && GFC_DECL_SAVED_DESCRIPTOR (orig_decl))
+    {
+      orig_decl = GFC_DECL_SAVED_DESCRIPTOR (orig_decl);
+      decl_type = TREE_TYPE (orig_decl);
+    }
 
-  /* Only pointer was privatized; cf. gfc_omp_clause_copy_ctor. */
-  if (DECL_P (OMP_CLAUSE_DECL (clause))
-      && GFC_DECL_ASSOCIATE_VAR_P (OMP_CLAUSE_DECL (clause)))
+  /* Only pointer association was privatized; cf. gfc_omp_clause_copy_ctr.
+     Scalar class pointers must not finalize or free their targets here.  */
+  if (DECL_P (orig_decl)
+      && (GFC_DECL_ASSOCIATE_VAR_P (orig_decl)
+         || GFC_DECL_GET_SCALAR_POINTER (orig_decl)
+         || gfc_is_class_pointer_type (decl_type)))
     return NULL_TREE;
 
-  if (DECL_ARTIFICIAL (OMP_CLAUSE_DECL (clause))
-      && DECL_LANG_SPECIFIC (OMP_CLAUSE_DECL (clause))
-      && GFC_DECL_SAVED_DESCRIPTOR (OMP_CLAUSE_DECL (clause)))
-    decl_type
-       = TREE_TYPE (GFC_DECL_SAVED_DESCRIPTOR (OMP_CLAUSE_DECL (clause)));
   if (gfc_is_polymorphic_nonptr (decl_type))
     {
       if (POINTER_TYPE_P (decl_type))
diff --git a/libgomp/testsuite/libgomp.fortran/pr120286.f90 
b/libgomp/testsuite/libgomp.fortran/pr120286.f90
new file mode 100644
index 000000000000..e45ed5539a62
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/pr120286.f90
@@ -0,0 +1,49 @@
+! { dg-do run }
+!
+! PR fortran/120286 - scalar class pointers in OpenMP private/firstprivate
+! clauses must preserve association status without taking ownership.
+
+program main
+  implicit none
+
+  type foo_t
+    integer :: dummy
+  end type foo_t
+
+  type fooPtr_t
+    class(foo_t), pointer :: p
+  end type fooPtr_t
+
+  type fooPtrStack_t
+    class(fooPtr_t), allocatable :: list(:)
+  end type fooPtrStack_t
+
+  type(fooPtrStack_t) :: x
+  class(foo_t), pointer :: ptr
+  integer :: it, n
+  logical :: ok
+
+  allocate (x%list(1))
+  allocate (x%list(1)%p)
+  x%list(1)%p%dummy = 7
+
+  do it = 1, 16
+!$omp parallel do default(none) num_threads(2) private(n, ptr) shared(x)
+    do n = 1, 1
+      ptr => x%list(n)%p
+    end do
+!$omp end parallel do
+  end do
+
+  if (.not. associated (x%list(1)%p)) stop 1
+  if (x%list(1)%p%dummy /= 7) stop 2
+
+  ptr => x%list(1)%p
+  ok = .false.
+
+!$omp parallel default(none) num_threads(1) firstprivate(ptr) shared(x, ok)
+  ok = associated (ptr, x%list(1)%p) .and. ptr%dummy == 7
+!$omp end parallel
+
+  if (.not. ok) stop 3
+end program main

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