diff --git a/libcxx/include/valarray b/libcxx/include/valarray
--- a/libcxx/include/valarray
+++ b/libcxx/include/valarray
@@ -923,10 +923,10 @@
 #endif // _LIBCPP_CXX03_LANG
 
     // unary operators:
-    valarray       operator+() const;
-    valarray       operator-() const;
-    valarray       operator~() const;
-    valarray<bool> operator!() const;
+    __val_expr<_UnaryOp<__unary_plus<_Tp>, const valarray&> >   operator+() const;
+    __val_expr<_UnaryOp<negate<_Tp>, const valarray&> >         operator-() const;
+    __val_expr<_UnaryOp<__bit_not<_Tp>, const valarray&> >      operator~() const;
+    __val_expr<_UnaryOp<logical_not<_Tp>, const valarray&> >    operator!() const;
 
     // computed assignment:
     _LIBCPP_INLINE_VISIBILITY
@@ -3300,63 +3300,35 @@
 #endif // _LIBCPP_CXX03_LANG
 
 template <class _Tp>
-valarray<_Tp>
+__val_expr<_UnaryOp<__unary_plus<_Tp>, const valarray<_Tp>&> >
 valarray<_Tp>::operator+() const
 {
-    valarray<value_type> __r;
-    size_t __n = size();
-    if (__n)
-    {
-        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
-        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
-            ::new ((void*)__r.__end_) value_type(+*__p);
-    }
-    return __r;
+    typedef _UnaryOp<__unary_plus<_Tp>, const valarray<_Tp>&> _Op;
+    return __val_expr<_Op>(_Op(__unary_plus<_Tp>(), *this));
 }
 
 template <class _Tp>
-valarray<_Tp>
+__val_expr<_UnaryOp<negate<_Tp>, const valarray<_Tp>&> >
 valarray<_Tp>::operator-() const
 {
-    valarray<value_type> __r;
-    size_t __n = size();
-    if (__n)
-    {
-        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
-        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
-            ::new ((void*)__r.__end_) value_type(-*__p);
-    }
-    return __r;
+    typedef _UnaryOp<negate<_Tp>, const valarray<_Tp>&> _Op;
+    return __val_expr<_Op>(_Op(negate<_Tp>(), *this));
 }
 
 template <class _Tp>
-valarray<_Tp>
+__val_expr<_UnaryOp<__bit_not<_Tp>, const valarray<_Tp>&> >
 valarray<_Tp>::operator~() const
 {
-    valarray<value_type> __r;
-    size_t __n = size();
-    if (__n)
-    {
-        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
-        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
-            ::new ((void*)__r.__end_) value_type(~*__p);
-    }
-    return __r;
+    typedef _UnaryOp<__bit_not<_Tp>, const valarray<_Tp>&> _Op;
+    return __val_expr<_Op>(_Op(__bit_not<_Tp>(), *this));
 }
 
 template <class _Tp>
-valarray<bool>
+__val_expr<_UnaryOp<logical_not<_Tp>, const valarray<_Tp>&> >
 valarray<_Tp>::operator!() const
 {
-    valarray<bool> __r;
-    size_t __n = size();
-    if (__n)
-    {
-        __r.__begin_ = __r.__end_ = allocator<bool>().allocate(__n);
-        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
-            ::new ((void*)__r.__end_) bool(!*__p);
-    }
-    return __r;
+    typedef _UnaryOp<logical_not<_Tp>, const valarray<_Tp>&> _Op;
+    return __val_expr<_Op>(_Op(logical_not<_Tp>(), *this));
 }
 
 template <class _Tp>
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
@@ -54,6 +54,13 @@
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == ~(2*v[i]));
     }
+    {
+        // Make sure we don't have dangling reference problems with unary expressions
+        std::valarray<int> a = {1, 2, 3};
+        std::valarray<int> b = {1, 2, 3};
+        auto c = ~a * b;
+        assert(c.size() == 3);
+    }
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
@@ -64,6 +64,13 @@
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == -2*v[i]);
     }
+    {
+        // Make sure we don't have dangling reference problems with unary expressions
+        std::valarray<int> a = {1, 2, 3};
+        std::valarray<int> b = {1, 2, 3};
+        auto c = -a * b;
+        assert(c.size() == 3);
+    }
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
@@ -40,6 +40,13 @@
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == !(v[i] + v[i]));
     }
+    {
+        // Make sure we don't have dangling reference problems with unary expressions
+        std::valarray<bool> a = {true, false, true};
+        std::valarray<int> b = {true, false, true};
+        auto c = !a && b;
+        assert(c.size() == 3);
+    }
 
-  return 0;
+    return 0;
 }
diff --git a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
--- a/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
+++ b/libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp
@@ -64,6 +64,13 @@
         for (std::size_t i = 0; i < v2.size(); ++i)
             assert(v2[i] == +2*v[i]);
     }
+    {
+        // Make sure we don't have dangling reference problems with unary expressions
+        std::valarray<int> a = {1, 2, 3};
+        std::valarray<int> b = {1, 2, 3};
+        auto c = +a * b;
+        assert(c.size() == 3);
+    }
 
-  return 0;
+    return 0;
 }