[gcc(refs/users/mikael/heads/refactor_descriptor_v205.01)] fortran: array descriptor: Move default descriptor initialization [PR122521]

https://gcc.gnu.org/g:9d6e333f8f8498b4db7015e71a824815d4d894f4

commit 9d6e333f8f8498b4db7015e71a824815d4d894f4
Author: Mikael Morin <[email protected]>
Date:   Sun Aug 2 11:08:52 2026 +0200

    fortran: array descriptor: Move default descriptor initialization [PR122521]
    
    Array allocatable local variables have their descriptor data pointer set to
    null on function entry to represent their unallocated initial status.  The
    dtype of allocatable and pointer arrays is also set on entry.  Move the code
    generating those default initializations of array descriptors to its own
    function in trans-descriptor.cc.
    
            PR fortran/122521
    
    gcc/fortran/ChangeLog:
    
            * trans-array.cc (gfc_trans_deferred_array): Move default descriptor
            initialization...
            * trans-descriptor.cc (gfc_init_descriptor_variable): ... here
            as a new function.
            * trans-descriptor.h (gfc_init_descriptor_variable): New
            declaration.

Diff:
---
 gcc/fortran/trans-array.cc      | 24 ++++++------------------
 gcc/fortran/trans-descriptor.cc | 28 ++++++++++++++++++++++++++++
 gcc/fortran/trans-descriptor.h  |  2 ++
 3 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index 91fa43b26831..1b77e1ee66f2 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -12448,34 +12448,22 @@ gfc_trans_deferred_array (gfc_symbol * sym, gfc_wrapped_block * block)
 
   /* NULLIFY the data pointer for non-saved allocatables, or for non-saved
      pointers when -fcheck=pointer is specified.  */
-  if (GFC_DESCRIPTOR_TYPE_P (type) && !sym->attr.save
-      && (sym->attr.allocatable
-	  || (sym->attr.pointer && (gfc_option.rtcheck & GFC_RTCHECK_POINTER))))
+  if (GFC_DESCRIPTOR_TYPE_P (type)
+      && (sym->attr.allocatable || sym->attr.pointer))
     {
-      gfc_conv_descriptor_data_set (&init, descriptor, null_pointer_node);
-      if (flag_coarray == GFC_FCOARRAY_LIB && sym->attr.codimension)
+      if (flag_coarray == GFC_FCOARRAY_LIB
+	  && sym->attr.codimension
+	  && !sym->attr.save)
 	{
 	  /* Declare the variable static so its array descriptor stays present
 	     after leaving the scope.  It may still be accessed through another
 	     image.  This may happen, for example, with the caf_mpi
 	     implementation.  */
 	  TREE_STATIC (descriptor) = 1;
-	  gfc_conv_descriptor_token_set (&init, descriptor, null_pointer_node);
 	}
+      gfc_init_descriptor_variable (&init, sym, descriptor);
     }
 
-  /* Set initial TKR for pointers and allocatables */
-  if (GFC_DESCRIPTOR_TYPE_P (type)
-      && (sym->attr.pointer || sym->attr.allocatable))
-    {
-      tree etype;
-
-      gcc_assert (sym->as && sym->as->rank>=0);
-      etype = gfc_get_element_type (type);
-      gfc_conv_descriptor_dtype_set (&init, descriptor,
-				     gfc_get_dtype_rank_type (sym->as->rank,
-							      etype));
-    }
   input_location = loc;
   gfc_init_block (&cleanup);
 
diff --git a/gcc/fortran/trans-descriptor.cc b/gcc/fortran/trans-descriptor.cc
index 8cee990206e4..aab7310265ab 100644
--- a/gcc/fortran/trans-descriptor.cc
+++ b/gcc/fortran/trans-descriptor.cc
@@ -746,6 +746,34 @@ gfc_init_absent_descriptor (stmtblock_t *block, tree descr)
 }
 
 
+/* Add code to BLOCK initializing the array descriptor DESCR corresponding to
+   the array variable SYM.  This is only used for variables needing a default
+   initialization of their descriptor.  Typically allocatable (array) variables,
+   that have an initial status of unallocated, are among them; they need their
+   data pointer set to nullptr.  */
+
+void
+gfc_init_descriptor_variable (stmtblock_t *block, gfc_symbol *sym, tree descr)
+{
+  /* NULLIFY the data pointer for non-saved allocatables, or for non-saved
+     pointers when -fcheck=pointer is specified.  */
+  if (!sym->attr.save
+      && (sym->attr.allocatable
+	  || (sym->attr.pointer && (gfc_option.rtcheck & GFC_RTCHECK_POINTER))))
+    {
+      gfc_conv_descriptor_data_set (block, descr, null_pointer_node);
+      if (flag_coarray == GFC_FCOARRAY_LIB && sym->attr.codimension)
+	gfc_conv_descriptor_token_set (block, descr, null_pointer_node);
+    }
+
+  gcc_assert (sym->as && sym->as->rank>=0);
+  tree etype = gfc_get_element_type (TREE_TYPE (descr));
+  gfc_conv_descriptor_dtype_set (block, descr,
+				 gfc_get_dtype_rank_type (sym->as->rank,
+							  etype));
+}
+
+
 /* For an array descriptor, get the total number of elements.  This is just
    the product of the extents along from_dim to to_dim.  */
 
diff --git a/gcc/fortran/trans-descriptor.h b/gcc/fortran/trans-descriptor.h
index 79786c32ecdf..e9006a229716 100644
--- a/gcc/fortran/trans-descriptor.h
+++ b/gcc/fortran/trans-descriptor.h
@@ -66,6 +66,8 @@ tree gfc_build_null_descriptor (tree type);
 void gfc_nullify_descriptor (stmtblock_t *block, tree);
 void gfc_init_result_descriptor (stmtblock_t *block, tree descr);
 void gfc_init_absent_descriptor (stmtblock_t *block, tree descr);
+void gfc_init_descriptor_variable (stmtblock_t *block, gfc_symbol *sym,
+				   tree descr);
 
 tree gfc_conv_descriptor_size (tree, int);
 tree gfc_conv_descriptor_cosize (tree, int, int);