lto.c (hash_canonical_type): Be sure we hash only types that need alias set.

	* lto.c (hash_canonical_type): Be sure we hash only types that
	need alias set.
	(gimple_register_canonical_type_1): Do not produce canonical
	types for types that do not need alias sets.
	* tree.c (gimple_canonical_types_compatible_p): Sanity check that
	we do not try to compute canonical type for type that does not need
	alias set.
	(verify_type): Drop FIXME for METHOD_TYPE, update FIXME for
	FUNCITON_TYPE.
	* tree.h (type_with_alias_set_p): New.

From-SVN: r223608

1 files changed, 17 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index accab4d..8b03446 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -12720,6 +12720,23 @@ gimple_canonical_types_compatible_p (const_tree t1, const_tree t2,
   if (t1 == NULL_TREE || t2 == NULL_TREE)
     return false;
 
+  /* We consider complete types always compatible with incomplete type.
+     This does not make sense for canonical type calculation and thus we
+     need to ensure that we are never called on it.
+
+     FIXME: For more correctness the function probably should have three modes
+	1) mode assuming that types are complete mathcing their structure
+	2) mode allowing incomplete types but producing equivalence classes
+	   and thus ignoring all info from complete types
+	3) mode allowing incomplete types to match complete but checking
+	   compatibility between complete types.
+
+     1 and 2 can be used for canonical type calculation. 3 is the real
+     definition of type compatibility that can be used i.e. for warnings during
+     declaration merging.  */
+
+  gcc_assert (!trust_type_canonical
+	      || (type_with_alias_set_p (t1) && type_with_alias_set_p (t2)));
   /* If the types have been previously registered and found equal
      they still are.  */
   if (TYPE_CANONICAL (t1) && TYPE_CANONICAL (t2)