Make variant's index part of the hash value

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@288554 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 0 deletions

diff --git a/include/memory b/include/memory
index 24361cc8e..e4cb58b8d 100644
--- a/include/memory
+++ b/include/memory
@@ -3345,6 +3345,17 @@ struct __scalar_hash<_Tp, 4>
     }
 };
 
+_LIBCPP_INLINE_VISIBILITY
+inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
+    struct _PairT {
+      size_t first;
+      size_t second;
+    };
+    typedef __scalar_hash<_PairT> _HashT;
+    const _PairT __p{__lhs, __rhs};
+    return _HashT()(__p);
+}
+
 template<class _Tp>
 struct _LIBCPP_TYPE_VIS_ONLY hash<_Tp*>
     : public unary_function<_Tp*, size_t>