diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4c052cc55bc0..9142af1bb061 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-09-18  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
+	* tree-vect-loop.c (vectorizable_live_operation): Fix type of
+	bitstart.
+
 2017-09-18  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 5d29ef5275cd..3140bbbbfff9 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -7091,7 +7091,7 @@ vectorizable_live_operation (gimple *stmt,
       vec_lhs = gimple_get_lhs (SLP_TREE_VEC_STMTS (slp_node)[vec_entry]);
 
       /* Get entry to use.  */
-      bitstart = build_int_cst (unsigned_type_node, vec_index);
+      bitstart = bitsize_int (vec_index);
       bitstart = int_const_binop (MULT_EXPR, bitsize, bitstart);
     }
   else