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

Can you please update the synopsis?

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

3

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

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!

include/valarray

public:
     operator>>=(const _Expr& __v) const;
 
     _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

test/std/numerics/numarray/template.indirect.array/indirect.array.assign/slice_assignment.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 valarray<value_type>& v) const;
+
+#include <valarray>
+#include <cassert>
+
+int main(int, char**)
+{
+    typedef std::valarray<double> matrix;
+
+    matrix m = { 0, 0, 0 };
+
+    m[std::slice(0, 3, 1)] = {1, 2, 3};
+
+    assert(m[0] == 1);
+    assert(m[1] == 2);
+    assert(m[2] == 3);
+
+    return 0;
+}