Hi,
this is patch I ended up testing. It ensures that canonical types of
copies I create are same as of originals C++ FE has its own refernece
type construction (cp_build_reference_type) and it creates additional
pointer types with TYPE_REF_IS_RVALUE set and it has different
TYPE_CANONICAL.
Obviously we do not see this in middle-end and we end up merging the
types despite fact they have different TYPE_CANONICAL.
I guess I can immitate the behaviour in fld_incomplete_type_of by
implementing my own variant of build_pointer_type that also matches
TYPE_CANONICAL of the pointer it creates. I wonder if there are better
solutions?
Honza
Index: tree.c
===================================================================
--- tree.c (revision 265807)
+++ tree.c (working copy)
@@ -5118,6 +5118,7 @@ fld_type_variant (tree first, tree t, st
TYPE_ADDR_SPACE (v) = TYPE_ADDR_SPACE (t);
TYPE_NAME (v) = TYPE_NAME (t);
TYPE_ATTRIBUTES (v) = TYPE_ATTRIBUTES (t);
+ TYPE_CANONICAL (v) = TYPE_CANONICAL (t);
add_tree_to_fld_list (v, fld);
return v;
}
@@ -5146,6 +5147,10 @@ fld_incomplete_type_of (tree t, struct f
else
first = build_reference_type_for_mode (t2, TYPE_MODE (t),
TYPE_REF_CAN_ALIAS_ALL (t));
+ gcc_assert (TYPE_CANONICAL (t2) != t2
+ && TYPE_CANONICAL (t2) == TYPE_CANONICAL (TREE_TYPE (t))
+ && TYPE_CANONICAL (first)
+ == TYPE_CANONICAL (TYPE_MAIN_VARIANT (t)));
add_tree_to_fld_list (first, fld);
return fld_type_variant (first, t, fld);
}
@@ -5169,6 +5174,7 @@ fld_incomplete_type_of (tree t, struct f
SET_TYPE_MODE (copy, VOIDmode);
SET_TYPE_ALIGN (copy, BITS_PER_UNIT);
TYPE_SIZE_UNIT (copy) = NULL;
+ TYPE_CANONICAL (copy) = TYPE_CANONICAL (t);
if (AGGREGATE_TYPE_P (t))
{
TYPE_FIELDS (copy) = NULL;
