diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8e062b9d55a..09da08d6176 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-12  Jakub Jelinek  <jakub@redhat.com>
+
+	* builtins.c (fold_builtin_memory_op): Avoid -Wsign-compare
+	warning.
+
 2010-08-12  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/45232
diff --git a/gcc/builtins.c b/gcc/builtins.c
index ad5d6aae048..9a79adbece2 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -8399,7 +8399,7 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
 	  if (readonly_data_expr (src)
 	      || (host_integerp (len, 1)
 		  && (MIN (src_align, dest_align) / BITS_PER_UNIT
-		      >= tree_low_cst (len, 1))))
+		      >= (unsigned HOST_WIDE_INT) tree_low_cst (len, 1))))
 	    {
 	      tree fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
 	      if (!fn)