From e0aaf744a53e3c710f3d6ee19a7b184f1a5a4da4 Mon Sep 17 00:00:00 2001
From: Gary Furnish <gfurnish@gfurnish.net>
Date: Mon, 5 Jun 2017 18:15:33 -0600
Subject: [PATCH] Fix integer rollover that triggers clang ubsan when U is
 unsigned

---
 include/boost/container/detail/copy_move_algo.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/boost/container/detail/copy_move_algo.hpp b/include/boost/container/detail/copy_move_algo.hpp
index 968f4ac..9044960 100644
--- a/include/boost/container/detail/copy_move_algo.hpp
+++ b/include/boost/container/detail/copy_move_algo.hpp
@@ -963,7 +963,8 @@ template
 inline typename container_detail::disable_if_trivially_destructible<I, void>::type
    destroy_alloc_n(Allocator &a, I f, U n)
 {
-   while(n--){
+   while(n){
+      --n;
       allocator_traits<Allocator>::destroy(a, boost::movelib::iterator_to_raw_pointer(f));
       ++f;
    }