Add return statement to slice_array and mask_array assignment. Closes PR20614.

This patch just adds the required return statements to slice_array::operator=
and mask_array::operator=.

Tests were added to check that the return value is the same as the object assigned
to.

llvm-svn: 215414

libcxx/include/valarray

@@ -1220,6 +1220,7 @@ slice_array<_Tp>::operator=(const slice_array& __sa) const
     const value_type* __s = __sa.__vp_;
     for (size_t __n = __size_; __n; --__n, __t += __stride_, __s += __sa.__stride_)
         *__t = *__s;
+    return *this;
 }
 
 template <class _Tp>
@@ -2090,6 +2091,7 @@ mask_array<_Tp>::operator=(const mask_array& __ma) const
     size_t __n = __1d_.size();
     for (size_t __i = 0; __i < __n; ++__i)
         __vp_[__1d_[__i]] = __ma.__vp_[__1d_[__i]];
+    return *this;
 }
 
 template <class _Tp>

libcxx/test/numerics/numarray/template.mask.array/mask.array.assign/mask_array.pass.cpp

@@ -18,6 +18,7 @@
 
 int main()
 {
+    {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     const std::size_t N1 = sizeof(a1)/sizeof(a1[0]);
     bool b1[N1] = {true,  false, false, true,  true,  false,
@@ -48,4 +49,18 @@ int main()
     assert(v1[13] == 13);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+    }
+    // Test return value of assignment
+    {
+    int a1[] = {0, 1, 2};
+    int a2[] = {3, 4, 5};
+    bool b1[] = {true, false, true};
+    std::valarray<int> v1(a1, 3);
+    std::valarray<int> v2(a2, 3);
+    std::valarray<bool> const vb1(b1, 3);
+    std::mask_array<int> m1 = v1[vb1];
+    std::mask_array<int> const m2 = v2[vb1];
+    std::mask_array<int> const & r = (m1 = m2);
+    assert(&r == &m1);
+    }
 }

libcxx/test/numerics/numarray/template.slice.array/slice.arr.assign/slice_array.pass.cpp

@@ -18,6 +18,7 @@
 
 int main()
 {
+    {
     int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
     int a2[] = {-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12};
     std::valarray<int> v1(a1, sizeof(a1)/sizeof(a1[0]));
@@ -40,4 +41,16 @@ int main()
     assert(v1[13] == -11);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
+    }
+    // Test return value of assignment.
+    {
+    int a1[] = {0, 1, 2};
+    int a2[] = {3, 4, 3};
+    std::valarray<int> v1(a1, 3);
+    const std::valarray<int> v2(a2, 3);
+    std::slice_array<int> s1 = v1[std::slice(1, 2, 3)];
+    std::slice_array<int> s2 = v1[std::slice(2, 2, 3)];
+    std::slice_array<int> const & s3 = (s1 = s2);
+    assert(&s1 == &s3);
+    }
 }