diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f74f2d3980b..6edc32675fa 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-05-10  Ben Elliston  <bje@au.ibm.com>
+
+	* tree.h: Include "hashtab.h".
+	(iterative_hash_expr): Use hashval_t in its prototype.
+	* Makefile.in (TREE_H): Add $(HASHTAB_H).
+
 2006-05-09  Steve Ellcey  <sje@cup.hp.com>
 
 	PR bootstrap/26872
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 807380a7143..93a5016995c 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -747,7 +747,7 @@ RTL_H = $(RTL_BASE_H) genrtl.h
 PARAMS_H = params.h params.def
 BUILTINS_DEF = builtins.def sync-builtins.def omp-builtins.def
 TREE_H = tree.h tree.def $(MACHMODE_H) tree-check.h $(BUILTINS_DEF) \
-          input.h statistics.h vec.h treestruct.def
+          input.h statistics.h vec.h treestruct.def $(HASHTAB_H)
 BASIC_BLOCK_H = basic-block.h bitmap.h sbitmap.h varray.h $(PARTITION_H) \
           hard-reg-set.h cfghooks.h $(OBSTACK_H)
 GCOV_IO_H = gcov-io.h gcov-iov.h auto-host.h
diff --git a/gcc/tree.h b/gcc/tree.h
index 742002a693f..fcd668659b9 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -22,6 +22,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #ifndef GCC_TREE_H
 #define GCC_TREE_H
 
+#include "hashtab.h"
 #include "machmode.h"
 #include "input.h"
 #include "statistics.h"
@@ -4266,7 +4267,7 @@ extern bool variably_modified_type_p (tree, tree);
 extern int tree_log2 (tree);
 extern int tree_floor_log2 (tree);
 extern int simple_cst_equal (tree, tree);
-extern unsigned int iterative_hash_expr (tree, unsigned int);
+extern hashval_t iterative_hash_expr (tree, hashval_t);
 extern int compare_tree_int (tree, unsigned HOST_WIDE_INT);
 extern int type_list_equal (tree, tree);
 extern int chain_member (tree, tree);