extern HOST_WIDE_INT new_alias_set (void);
extern HOST_WIDE_INT get_varargs_alias_set (void);
extern HOST_WIDE_INT get_frame_alias_set (void);
-extern void record_base_value (unsigned int, rtx, int);
extern bool component_uses_parent_alias_set (tree);
+extern bool alias_set_subset_of (HOST_WIDE_INT, HOST_WIDE_INT);
+
+/* This alias set can be used to force a memory to conflict with all
+ other memories, creating a barrier across which no memory reference
+ can move. Note that there are other legacy ways to create such
+ memory barriers, including an address of SCRATCH. */
+#define ALIAS_SET_MEMORY_BARRIER ((HOST_WIDE_INT) -1)
#endif /* GCC_ALIAS_H */