commit 53c8e2503773041281d4cce886ab7c136e1e7b15
author Marshall Clow <mclow.lists@gmail.com> Tue Sep 11 18:33:45 2018 +0000
committer Marshall Clow <mclow.lists@gmail.com> Tue Sep 11 18:33:45 2018 +0000
tree 6d18f15dccf204c73e399fb8b5d602151ca6a8a9
parent 5a86ba0aa0d95d6ced5df6be89721916e68da318

Fix PR# 38900 - don't call swap inside of random_shuffle when we'd be swapping an element with itself

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@341975 91177308-0d34-0410-b5e6-96231b3b80d8

include/algorithm

diff --git a/include/algorithm b/include/algorithm
index ee2a54d..55e1f9f 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -2987,7 +2987,8 @@
         for (--__last; __first < __last; ++__first, --__d)
         {
             difference_type __i = __rand(__d);
-            swap(*__first, *(__first + __i));
+            if (__i != difference_type(0))
+	            swap(*__first, *(__first + __i));
         }
     }
 }