From: Eric Botcazou <ebotcazou@adacore.com>
Date: Tue, 12 Dec 2023 09:17:19 +0000 (+0100)
Subject: ada: Fix bogus Constraint_Error on allocator for access to array of access type
X-Git-Tag: basepoints/gcc-15~3077
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bcf7ebba9115cc1e0e1be4c6e00728e0e99e5fc8;p=thirdparty%2Fgcc.git

ada: Fix bogus Constraint_Error on allocator for access to array of access type

This occurs because the access element type is not its own TYPE_CANONICAL,
which creates a discrepancy between the aliasing support code, which deals
with types directly, and the middle-end which looks at TYPE_CANONICAL only.

gcc/ada/

	* gcc-interface/decl.cc (gnat_to_gnu_entity) <E_Array_Type>: Use the
	TYPE_CANONICAL of types when it comes to aliasing.
	* gcc-interface/utils.cc (relate_alias_sets): Likewise.
---

diff --git a/gcc/ada/gcc-interface/decl.cc b/gcc/ada/gcc-interface/decl.cc
index 221baebb554e..93cfcb74fbf9 100644
--- a/gcc/ada/gcc-interface/decl.cc
+++ b/gcc/ada/gcc-interface/decl.cc
@@ -2185,8 +2185,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	if (COMPLETE_TYPE_P (gnu_fat_type))
 	  {
 	    fld = TYPE_FIELDS (gnu_fat_type);
-	    if (TYPE_ALIAS_SET_KNOWN_P (TREE_TYPE (fld)))
-	      ptr_set = TYPE_ALIAS_SET (TREE_TYPE (fld));
+	    if (TYPE_ALIAS_SET_KNOWN_P (TYPE_CANONICAL (TREE_TYPE (fld))))
+	      ptr_set = TYPE_ALIAS_SET (TYPE_CANONICAL (TREE_TYPE (fld)));
 	    TREE_TYPE (fld) = ptr_type_node;
 	    TREE_TYPE (DECL_CHAIN (fld)) = gnu_ptr_template;
 	    TYPE_DECL_SUPPRESS_DEBUG (TYPE_STUB_DECL (gnu_fat_type)) = 0;
@@ -2417,7 +2417,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 	else
 	  TREE_TYPE (fld) = build_pointer_type (tem);
 	if (ptr_set != -1)
-	  TYPE_ALIAS_SET (TREE_TYPE (fld)) = ptr_set;
+	  TYPE_ALIAS_SET (TYPE_CANONICAL (TREE_TYPE (fld))) = ptr_set;
 
 	/* If the maximum size doesn't overflow, use it.  */
 	if (gnu_max_size
diff --git a/gcc/ada/gcc-interface/utils.cc b/gcc/ada/gcc-interface/utils.cc
index bc063c203875..b3aae5bda52f 100644
--- a/gcc/ada/gcc-interface/utils.cc
+++ b/gcc/ada/gcc-interface/utils.cc
@@ -1867,7 +1867,8 @@ relate_alias_sets (tree new_type, tree old_type, enum alias_set_op op)
 		      && TYPE_NONALIASED_COMPONENT (new_type)
 			 != TYPE_NONALIASED_COMPONENT (old_type)));
 
-      TYPE_ALIAS_SET (new_type) = get_alias_set (old_type);
+      /* The alias set always lives on the TYPE_CANONICAL.  */
+      TYPE_ALIAS_SET (TYPE_CANONICAL (new_type)) = get_alias_set (old_type);
       break;
 
     case ALIAS_SET_SUBSET: