diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 392fd1d76634..625a880d5519 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-30  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	PR c++/58708
+	* parser.c (make_string_pack): Use double_int::from_buffer.
+
 2014-01-30  Marek Polacek  <polacek@redhat.com>
 
 	PR c/59940
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0636445198bf..a53597d205e5 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -3808,7 +3808,8 @@ make_string_pack (tree value)
 {
   tree charvec;
   tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
-  const char *str = TREE_STRING_POINTER (value);
+  const unsigned char *str
+    = (const unsigned char *) TREE_STRING_POINTER (value);
   int sz = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (value))));
   int len = TREE_STRING_LENGTH (value) / sz - 1;
   tree argvec = make_tree_vec (2);
@@ -3821,23 +3822,10 @@ make_string_pack (tree value)
 
   /* Fill in CHARVEC with all of the parameters.  */
   charvec = make_tree_vec (len);
-  if (sz == 1)
-    {
-      for (int i = 0; i < len; ++i)
-	TREE_VEC_ELT (charvec, i) = build_int_cst (str_char_type_node, str[i]);
-    }
-  else if (sz == 2)
-    {
-      const uint16_t *num = (const uint16_t *)str;
-      for (int i = 0; i < len; ++i)
-	TREE_VEC_ELT (charvec, i) = build_int_cst (str_char_type_node, num[i]);
-    }
-  else if (sz == 4)
-    {
-      const uint32_t *num = (const uint32_t *)str;
-      for (int i = 0; i < len; ++i)
-	TREE_VEC_ELT (charvec, i) = build_int_cst (str_char_type_node, num[i]);
-    }
+  for (int i = 0; i < len; ++i)
+    TREE_VEC_ELT (charvec, i)
+      = double_int_to_tree (str_char_type_node,
+			    double_int::from_buffer (str + i * sz, sz));
 
   /* Build the argument packs.  */
   SET_ARGUMENT_PACK_ARGS (argpack, charvec);