[gcc r12-10501] Fix crash on access-to-incomplete type

[Eric Botcazou]

https://gcc.gnu.org/g:12a3ba2be46e86ff1bffa5c876b6b17fe4929be3

commit r12-10501-g12a3ba2be46e86ff1bffa5c876b6b17fe4929be3
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Mon Jun 10 12:12:21 2024 +0200

    Fix crash on access-to-incomplete type
    
    This just adds the missing guard.
    
    gcc/ada/
            PR ada/114708
            * exp_util.adb (Finalize_Address): Add guard for incomplete types.
    
    gcc/testsuite/
            * gnat.dg/incomplete8.adb: New test.

Diff:
---
 gcc/ada/exp_util.adb                  |  6 ++++++
 gcc/testsuite/gnat.dg/incomplete8.adb | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index e18b2ace44b..5eedd72f5bc 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -5866,6 +5866,12 @@ package body Exp_Util is
 
       Utyp := Underlying_Type (Base_Type (Utyp));
 
+      --  Handle incomplete types
+
+      if No (Utyp) then
+         return Empty;
+      end if;
+
       --  Deal with untagged derivation of private views. If the parent is
       --  now known to be protected, the finalization routine is the one
       --  defined on the corresponding record of the ancestor (corresponding
diff --git a/gcc/testsuite/gnat.dg/incomplete8.adb b/gcc/testsuite/gnat.dg/incomplete8.adb
new file mode 100644
index 00000000000..63fef59e866
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/incomplete8.adb
@@ -0,0 +1,22 @@
+-- PR ada/114708
+-- Reported by Jere <jhb.chat@gmail.com>
+
+-- { dg-do compile }
+
+procedure Incomplete8 is
+
+  generic
+    type Element_Type(<>);
+  package Test_Incomplete_Formal is
+    type Element_Access is access Element_Type;
+  end Test_Incomplete_Formal;
+
+  type Node;
+
+  package P is new Test_Incomplete_Formal(Node);
+
+  type Node is limited null record;
+   
+begin
+  null;
+end;