[gcc r11-8988] Fix internal error on pointer-to-pointer binding in LTO mode

[Eric Botcazou <ebotcazou@gcc.gnu.org>]

https://gcc.gnu.org/g:e94730e51afdaf2d61c8c89c89c39453dee7c6de

commit r11-8988-ge94730e51afdaf2d61c8c89c89c39453dee7c6de
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Tue Sep 14 10:44:34 2021 +0200

    Fix internal error on pointer-to-pointer binding in LTO mode
    
    gcc/ada/
            * gcc-interface/utils.c (update_pointer_to): Set TYPE_CANONICAL on
            pointer and reference types.

Diff:
---
 gcc/ada/gcc-interface/utils.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/gcc-interface/utils.c b/gcc/ada/gcc-interface/utils.c
index b71f7489066..dde0d58e6d2 100644
--- a/gcc/ada/gcc-interface/utils.c
+++ b/gcc/ada/gcc-interface/utils.c
@@ -4329,6 +4329,7 @@ update_pointer_to (tree old_type, tree new_type)
 	    TREE_TYPE (t) = new_type;
 	    if (TYPE_NULL_BOUNDS (t))
 	      TREE_TYPE (TREE_OPERAND (TYPE_NULL_BOUNDS (t), 0)) = new_type;
+	    TYPE_CANONICAL (t) = TYPE_CANONICAL (TYPE_POINTER_TO (new_type));
 	  }
 
       /* Chain REF and its variants at the end.  */
@@ -4345,7 +4346,10 @@ update_pointer_to (tree old_type, tree new_type)
       /* Now adjust them.  */
       for (; ref; ref = TYPE_NEXT_REF_TO (ref))
 	for (t = TYPE_MAIN_VARIANT (ref); t; t = TYPE_NEXT_VARIANT (t))
-	  TREE_TYPE (t) = new_type;
+	  {
+	    TREE_TYPE (t) = new_type;
+	    TYPE_CANONICAL (t) = TYPE_CANONICAL (TYPE_REFERENCE_TO (new_type));
+	  }
 
       TYPE_POINTER_TO (old_type) = NULL_TREE;
       TYPE_REFERENCE_TO (old_type) = NULL_TREE;