Add slice_array operator= valarray overload

[zoecarver]

Summary

Add the slice_array::operator=(const std::valarray<T>& val_arr) overload. Fixes llvm.org/PR40792.

[zoecarver]

Other than more tests, do I need to update this patch in any way?

[ldionne]

include/valarray

1267 ↗

(On Diff #188606)

Can you please update the synopsis?

test/std/numerics/numarray/template.indirect.array/indirect.array.assign/slice_assignment.pass.cpp

3 ↗

(On Diff #188606)

This test is in the wrong file. It should be merged with libcxx/test/std/numerics/numarray/template.slice.array/slice.arr.assign/valarray.pass.cpp (which was not testing the right thing unless I'm mistaken).

24 ↗

(On Diff #188606)

Can you create a slice_array variable here to make sure we return the right type (and hence are testing the right operator=?

Also, we should test that slice_array::operator= returns void.

[zoecarver]

• Rebase off master
• Address review comments

[ldionne]

LGTM once CI passes.

Even better (IMO) would be to split off the tests for void operator=(const T& value) const; into a separate file, since that was most likely an oversight.

[zoecarver]

• Rebase off master
• Split into two tests

[zoecarver]

By the way, I had to disable the added tests in C++03 mode.

I'll commit once the buildbots are green.

[ldionne]

We use tricks like this in other valarray tests to workaround the lack of initializer_list:

int a1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
std::valarray<int> v1(a1, sizeof(a1)/sizeof(a1[0]));

Can we use the same trick here and enable the tests in C++03? I think it would be good for consistency.

[zoecarver]

• Rebase off master
• Support template.pass.cpp in C++03 mode

[zoecarver]

Can we use the same trick here and enable the tests in C++03? I think it would be good for consistency.

@ldionne I did that for template.pass.cpp but kept the initializer list test in valarray.pass.cpp because we already have a test without initializer lists (that is enabled in C++03 mode).

[ldionne]

Thanks!

libcxx/include/valarray

public:
     void operator-= (const valarray<value_type>& v) const;
     void operator^= (const valarray<value_type>& v) const;
     void operator&= (const valarray<value_type>& v) const;
     void operator|= (const valarray<value_type>& v) const;
     void operator<<=(const valarray<value_type>& v) const;
     void operator>>=(const valarray<value_type>& v) const;
 
     void operator=(const value_type& x) const;
+    void operator=(const valarray<T>& val_arr) const;
 
     slice_array() = delete;
 };
 
 class gslice
 {
 public:
     gslice();
public:
     slice_array(slice_array const&) = default;
 
     _LIBCPP_INLINE_VISIBILITY
     const slice_array& operator=(const slice_array& __sa) const;
 
     _LIBCPP_INLINE_VISIBILITY
     void operator=(const value_type& __x) const;
 
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const valarray<value_type>& __va) const;
+
 private:
     _LIBCPP_INLINE_VISIBILITY
     slice_array(const slice& __sl, const valarray<value_type>& __v)
         : __vp_(const_cast<value_type*>(__v.__begin_ + __sl.start())),
           __size_(__sl.size()),
           __stride_(__sl.stride())
         {}
 

 slice_array<_Tp>::operator=(const _Expr& __v) const
 {
     value_type* __t = __vp_;
     for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
         *__t = __v[__i];
 }
 
 template <class _Tp>
+inline void
+slice_array<_Tp>::operator=(const valarray<value_type>& __va) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __va.size(); ++__i, __t += __stride_)
+        *__t = __va[__i];
+}
+
+template <class _Tp>
 template <class _Expr>
 inline
 typename enable_if
 <
     __is_val_expr<_Expr>::value,
     void
 >::type
 slice_array<_Tp>::operator*=(const _Expr& __v) const

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

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <valarray>
+
+// template <class T> class slice_array
+
+// void operator=(const T& value) const;
+
+#include <valarray>
+#include <cassert>
+
+#include "test_macros.h"
+
+int main(int, char**)
+{
+    double a[] = { 0, 0, 0 };
+    std::valarray<double> m(a, sizeof(a)/sizeof(a[0]));
+    std::slice_array<double> s = m[std::slice(0, 3, 1)];
+    s = 42;
+    assert(m[0] == 42);
+    assert(m[1] == 42);
+    assert(m[2] == 42);
+
+    ASSERT_SAME_TYPE(decltype(s = 42), void);
+
+    return 0;
+}

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

 #include "test_macros.h"
 
 int main(int, char**)
 {
     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};
     std::valarray<int> v1(a1, sizeof(a1)/sizeof(a1[0]));
     std::valarray<int> v2(a2, sizeof(a2)/sizeof(a2[0]));
-    v1[std::slice(1, 5, 3)] = v2;
+    std::slice_array<int> s1 = v1[std::slice(1, 5, 3)];
+    s1 = v2;
     assert(v1.size() == 16);
     assert(v1[ 0] ==  0);
     assert(v1[ 1] == -1);
     assert(v1[ 2] ==  2);
     assert(v1[ 3] ==  3);
     assert(v1[ 4] == -2);
     assert(v1[ 5] ==  5);
     assert(v1[ 6] ==  6);
     assert(v1[ 7] == -3);
     assert(v1[ 8] ==  8);
     assert(v1[ 9] ==  9);
     assert(v1[10] == -4);
     assert(v1[11] == 11);
     assert(v1[12] == 12);
     assert(v1[13] == -5);
     assert(v1[14] == 14);
     assert(v1[15] == 15);
 
+    ASSERT_SAME_TYPE(decltype(s1 = v2), void);
+
+// The initializer list constructor is disabled in C++03 mode.
+#if TEST_STD_VER > 03
+    std::valarray<double> m = { 0, 0, 0 };
+    std::slice_array<double> s2 = m[std::slice(0, 3, 1)];
+    s2 = { 1, 2, 3 };
+    assert(m[0] == 1);
+    assert(m[1] == 2);
+    assert(m[2] == 3);
+
+    ASSERT_SAME_TYPE(decltype(s2 = {1, 2, 3}), void);
+#endif // TEST_STD_VER > 03
+
     return 0;
 }