Add variadic ctor and CTAD to zip_iterator

Fixes: NVIDIA#4110

Author: bernhardmgruber

thrust/testing/zip_iterator.cu

@@ -57,17 +57,22 @@ struct TestZipIteratorManipulation
     sequence(v2.begin(), v2.end());
 
     using IteratorTuple = tuple<typename Vector::iterator, typename Vector::iterator>;
+    IteratorTuple t     = make_tuple(v0.begin(), v1.begin());
+    using ZipIterator   = zip_iterator<IteratorTuple>;
 
-    IteratorTuple t = make_tuple(v0.begin(), v1.begin());
-
-    using ZipIterator = zip_iterator<IteratorTuple>;
-
-    // test construction
+    // test construction from tuple
     ZipIterator iter0 = make_zip_iterator(t);
     ASSERT_EQUAL(true, iter0 == ZipIterator{t});
-
     ASSERT_EQUAL_QUIET(v0.begin(), get<0>(iter0.get_iterator_tuple()));
     ASSERT_EQUAL_QUIET(v1.begin(), get<1>(iter0.get_iterator_tuple()));
+    static_assert(::cuda::std::is_same_v<decltype(zip_iterator{t}), ZipIterator>); // CTAD
+
+    // test construction from pack
+    ZipIterator iter0_pack = make_zip_iterator(v0.begin(), v1.begin());
+    ASSERT_EQUAL(true, (iter0_pack == ZipIterator{v0.begin(), v1.begin()}));
+    ASSERT_EQUAL_QUIET(v0.begin(), get<0>(iter0_pack.get_iterator_tuple()));
+    ASSERT_EQUAL_QUIET(v1.begin(), get<1>(iter0_pack.get_iterator_tuple()));
+    static_assert(::cuda::std::is_same_v<decltype(zip_iterator{v0.begin(), v1.begin()}), ZipIterator>); // CTAD
 
     // test dereference
     ASSERT_EQUAL(*v0.begin(), get<0>(*iter0));
@@ -429,7 +434,7 @@ void TestZipIteratorCopyAoSToSoA()
 
   thrust::copy(d_aos.begin(), d_aos.end(), h_soa);
   ASSERT_EQUAL_QUIET(make_tuple(7, 13), h_soa[0]);
-};
+}
 DECLARE_UNITTEST(TestZipIteratorCopyAoSToSoA);
 
 void TestZipIteratorCopySoAToAoS()

thrust/thrust/iterator/zip_iterator.h

@@ -195,6 +195,15 @@ class _CCCL_DECLSPEC_EMPTY_BASES zip_iterator : public detail::make_zip_iterator
       : m_iterator_tuple(iterator_tuple)
   {}
 
+  //! This constructor creates a new \p zip_iterator from a pack of iterators.
+  //!
+  //! \param iterators A pack of iterators to zip.
+  template <typename... Iterators,
+            ::cuda::std::enable_if_t<(::cuda::std::input_or_output_iterator<Iterators> && ...), int> = 0>
+  _CCCL_HOST_DEVICE zip_iterator(Iterators... iterators)
+      : m_iterator_tuple(::cuda::std::move(iterators)...)
+  {}
+
   //! This copy constructor creates a new \p zip_iterator from another \p zip_iterator.
   //!
   //! \param other The \p zip_iterator to copy.
@@ -296,6 +305,13 @@ class _CCCL_DECLSPEC_EMPTY_BASES zip_iterator : public detail::make_zip_iterator
   //! \endcond
 };
 
+template <typename... Iterators>
+_CCCL_HOST_DEVICE zip_iterator(_CUDA_VSTD::tuple<Iterators...>) -> zip_iterator<_CUDA_VSTD::tuple<Iterators...>>;
+
+template <typename... Iterators,
+          ::cuda::std::enable_if_t<(::cuda::std::input_or_output_iterator<Iterators> && ...), int> = 0>
+_CCCL_HOST_DEVICE zip_iterator(Iterators...) -> zip_iterator<_CUDA_VSTD::tuple<Iterators...>>;
+
 //! \p make_zip_iterator creates a \p zip_iterator from a \p tuple of iterators.
 //!
 //! \param t The \p tuple of iterators to copy.
@@ -308,17 +324,17 @@ make_zip_iterator(_CUDA_VSTD::tuple<Iterators...> t)
   return zip_iterator<_CUDA_VSTD::tuple<Iterators...>>(t);
 }
 
-//! \p make_zip_iterator creates a \p zip_iterator from
-//! iterators.
+//! \p make_zip_iterator creates a \p zip_iterator from iterators.
 //!
 //! \param its The iterators to copy.
 //! \return A newly created \p zip_iterator which zips the iterators.
 //!
 //! \see zip_iterator
-template <typename... Iterators>
+template <typename... Iterators,
+          ::cuda::std::enable_if_t<(::cuda::std::input_or_output_iterator<Iterators> && ...), int> = 0>
 inline _CCCL_HOST_DEVICE zip_iterator<_CUDA_VSTD::tuple<Iterators...>> make_zip_iterator(Iterators... its)
 {
-  return make_zip_iterator(_CUDA_VSTD::make_tuple(its...));
+  return zip_iterator<_CUDA_VSTD::tuple<Iterators...>>(::cuda::std::move(its)...);
 }
 
 //! \} // end fancyiterators