[gcc r12-7526] Fortran: Fix gfc_maybe_dereference_var [PR104430][PR99585]

[Tobias Burnus <burnus@gcc.gnu.org>]

https://gcc.gnu.org/g:c0134b7383992aab5c1a91440dbdd8fbb747169c

commit r12-7526-gc0134b7383992aab5c1a91440dbdd8fbb747169c
Author: Tobias Burnus <tobias@codesourcery.com>
Date:   Mon Mar 7 22:11:33 2022 +0100

    Fortran: Fix gfc_maybe_dereference_var [PR104430][PR99585]
    
            PR fortran/99585
            PR fortran/104430
    
    gcc/fortran/ChangeLog:
    
            * trans-expr.cc (conv_parent_component_references): Fix comment;
            simplify comparison.
            (gfc_maybe_dereference_var): Avoid d referencing a nonpointer.
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/class_result_10.f90: New test.

Diff:
---
 gcc/fortran/trans-expr.cc                     |  6 ++--
 gcc/testsuite/gfortran.dg/class_result_10.f90 | 52 +++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index c9d9a916c28..71d037101d4 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -2805,9 +2805,9 @@ conv_parent_component_references (gfc_se * se, gfc_ref * ref)
   dt = ref->u.c.sym;
   c = ref->u.c.component;
 
-  /* Return if the component is in the parent type.  */
+  /* Return if the component is in this type, i.e. not in the parent type.  */
   for (cmp = dt->components; cmp; cmp = cmp->next)
-    if (strcmp (c->name, cmp->name) == 0)
+    if (c == cmp)
       return;
 
   /* Build a gfc_ref to recursively call gfc_conv_component_ref.  */
@@ -2867,6 +2867,8 @@ tree
 gfc_maybe_dereference_var (gfc_symbol *sym, tree var, bool descriptor_only_p,
 			   bool is_classarray)
 {
+  if (!POINTER_TYPE_P (TREE_TYPE (var)))
+    return var;
   if (is_CFI_desc (sym, NULL))
     return build_fold_indirect_ref_loc (input_location, var);
 
diff --git a/gcc/testsuite/gfortran.dg/class_result_10.f90 b/gcc/testsuite/gfortran.dg/class_result_10.f90
new file mode 100644
index 00000000000..a4d29ab9c1d
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/class_result_10.f90
@@ -0,0 +1,52 @@
+! { dg-do run}
+
+
+! PR fortran/99585
+
+module m2
+  type t
+     class(*), pointer :: bar(:)
+  end type
+  type t2
+     class(t), allocatable :: my(:)
+  end type t2
+contains
+  function f (x, y) result(z)
+    class(t) :: x(:)
+    class(t) :: y(size(x(1)%bar))
+    type(t)  :: z(size(x(1)%bar))
+  end
+  function g (x) result(z)
+    class(t) :: x(:)
+    type(t)  :: z(size(x(1)%bar))
+  end
+  subroutine s ()
+    class(t2), allocatable :: a(:), b(:), c(:), d(:)
+    class(t2), pointer     :: p(:)
+    c(1)%my = f (a(1)%my, b(1)%my)
+    d(1)%my = g (p(1)%my)
+  end
+end
+
+! Contributed by  G. Steinmetz:
+! PR fortran/104430
+
+module m
+   type t
+      integer :: a
+   end type
+contains
+   function f(x) result(z)
+      class(t) :: x(:)
+      type(t) :: z(size(x%a))
+      z%a = 42
+   end
+end
+program p
+   use m
+   class(t), allocatable :: y(:), z(:)
+   allocate (y(32))
+   z = f(y)
+   if (size(z) /= 32) stop 1
+   if (any (z%a /= 42)) stop 2
+end