Ada: Fix ICE in fld_incomplete_type_of when building GtkAda with LTO (2)

The change incorrectly resets the alias set of the old pointer/reference,
which leads to the miscompilation of a few ACATS tests on some platforms.

gcc/ada/
	PR ada/123060
	* gcc-interface/utils.cc (update_pointer_to): Preserve the alias
	sets present on the old pointer and old reference, if any.

diff --git a/gcc/ada/gcc-interface/utils.cc b/gcc/ada/gcc-interface/utils.cc
index 62587cdb91d0d1d50b2be99f7ef101031451e6a7..9176ec29d566e160aa50f9816fe025398130469f 100644 (file)
--- a/gcc/ada/gcc-interface/utils.cc
+++ b/gcc/ada/gcc-interface/utils.cc
@@ -4680,15 +4680,24 @@ update_pointer_to (tree old_type, tree new_type)
          /* If there is no pointer pointing to NEW_TYPE yet, re-compute the
             TYPE_CANONICAL of the old pointer but pointing to NEW_TYPE, like
             build_pointer_type would have done for such a pointer, because we
-            will propagate it in the adjustment loop below.  */
+            will propagate it in the adjustment loop below.  But make sure to
+            preserve an alias set already present on the old pointer.  */
          if (TYPE_STRUCTURAL_EQUALITY_P (new_type))
            SET_TYPE_STRUCTURAL_EQUALITY (old_ptr);
          else if (TYPE_CANONICAL (new_type) != new_type
                   || (TYPE_REF_CAN_ALIAS_ALL (old_ptr)
                       && !lookup_attribute ("may_alias",
                                             TYPE_ATTRIBUTES (new_type))))
-           TYPE_CANONICAL (old_ptr)
-             = build_pointer_type (TYPE_CANONICAL (new_type));
+           {
+             alias_set_type set;
+             if (TYPE_STRUCTURAL_EQUALITY_P (old_ptr))
+               set = TYPE_ALIAS_SET (old_ptr);
+             else
+               set = TYPE_ALIAS_SET (TYPE_CANONICAL (old_ptr));
+             TYPE_CANONICAL (old_ptr)
+               = build_pointer_type (TYPE_CANONICAL (new_type));
+             TYPE_ALIAS_SET (TYPE_CANONICAL (old_ptr)) = set;
+           }
        }
 
       /* Now adjust them.  */
@@ -4716,15 +4725,24 @@ update_pointer_to (tree old_type, tree new_type)
          /* If there is no reference pointing to NEW_TYPE yet, re-compute the
             TYPE_CANONICAL of the old reference but pointing to NEW_TYPE, like
             build_reference_type would have done for such a reference, because
-            we will propagate it in the adjustment loop below.  */
+            we will propagate it in the adjustment loop below.  But make sure
+            to preserve an alias set already present on the old reference.  */
          if (TYPE_STRUCTURAL_EQUALITY_P (new_type))
            SET_TYPE_STRUCTURAL_EQUALITY (old_ref);
          else if (TYPE_CANONICAL (new_type) != new_type
                   || (TYPE_REF_CAN_ALIAS_ALL (old_ref)
                       && !lookup_attribute ("may_alias",
                                             TYPE_ATTRIBUTES (new_type))))
-           TYPE_CANONICAL (old_ref)
-             = build_reference_type (TYPE_CANONICAL (new_type));
+           {
+             alias_set_type set;
+             if (TYPE_STRUCTURAL_EQUALITY_P (old_ref))
+               set = TYPE_ALIAS_SET (old_ref);
+             else
+               set = TYPE_ALIAS_SET (TYPE_CANONICAL (old_ref));
+             TYPE_CANONICAL (old_ref)
+               = build_reference_type (TYPE_CANONICAL (new_type));
+             TYPE_ALIAS_SET (TYPE_CANONICAL (old_ref)) = set;
+           }
        }
 
       /* Now adjust them.  */