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Implement P2248R8: Enable list-initialization for algorithms #2398

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745544f
Implement P2248R8: Enable list-initialization for algorithms
rarutyun Jul 9, 2025
7f0ec2b
Add default template argument tests. Improve replace_copy tests
rarutyun Aug 26, 2025
a1561db
Implement empty list initialization for uninitialized_fill[_n]
rarutyun Aug 29, 2025
f1b47c6
Add tests for uninitialized_fill[_n] for hetero backend
rarutyun Sep 3, 2025
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36 changes: 24 additions & 12 deletions include/oneapi/dpl/pstl/glue_algorithm_defs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,8 @@ template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
find_if_not(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);

Expand Down Expand Up @@ -104,7 +105,8 @@ adjacent_find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardItera

// [alg.count]

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<
_ExecutionPolicy, typename ::std::iterator_traits<_ForwardIterator>::difference_type>
count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
Expand All @@ -126,12 +128,14 @@ oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Forward
search(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
_ForwardIterator2 __s_last);

template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
template <class _ExecutionPolicy, class _ForwardIterator, class _Size,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type, class _BinaryPredicate>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
const _Tp& __value, _BinaryPredicate __pred);

template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator, class _Size,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
const _Tp& __value);
Expand Down Expand Up @@ -189,33 +193,39 @@ transform_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIter

// [alg.replace]

template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy>
replace_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
const _Tp& __new_value);

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy>
replace(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value,
const _Tp& __new_value);

template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryPredicate, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryPredicate,
class _Tp = typename std::iterator_traits<_ForwardIterator2>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
replace_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
_ForwardIterator2 __result, _UnaryPredicate __pred, const _Tp& __new_value);

template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2,
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@danhoeflinger danhoeflinger Nov 17, 2025

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Doesn't the paper conclude not to make any changes to replace_copy for non ranges api?

class _Tp = typename std::iterator_traits<_ForwardIterator2>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
replace_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
const _Tp& __old_value, const _Tp& __new_value);

// [alg.fill]

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy>
fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);

template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator, class _Size,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __count, const _Tp& __value);

Expand All @@ -235,7 +245,8 @@ oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Forward
remove_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
_ForwardIterator2 __result, _Predicate __pred);

template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2,
class _Tp = typename std::iterator_traits<_ForwardIterator1>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
remove_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
const _Tp& __value);
Expand All @@ -244,7 +255,8 @@ template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
remove_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred);

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
remove(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);

Expand Down
6 changes: 4 additions & 2 deletions include/oneapi/dpl/pstl/glue_memory_defs.h
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Expand Up @@ -45,11 +45,13 @@ uninitialized_move_n(_ExecutionPolicy&& __exec, _InputIterator __first, _Size __

// [uninitialized.fill]

template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy>
uninitialized_fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);

template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
template <class _ExecutionPolicy, class _ForwardIterator, class _Size,
class _Tp = typename std::iterator_traits<_ForwardIterator>::value_type>
oneapi::dpl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
uninitialized_fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, const _Tp& __value);

Expand Down
82 changes: 82 additions & 0 deletions test/parallel_api/algorithm/alg.modifying.operations/fill.pass.cpp
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Expand Up @@ -97,6 +97,85 @@ test_fill_by_type(::std::size_t n)
#endif
}

void test_empty_list_initialization_for_fill()
{
{
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
oneapi::dpl::fill(oneapi::dpl::execution::seq, v.begin(), v.end(), {});
EXPECT_TRUE(std::count(v.begin(), v.end(), 0) == v.size(), "a sequence is not filled properly by oneapi::dpl::fill with `seq` policy");
}
{
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
oneapi::dpl::fill(oneapi::dpl::execution::unseq, v.begin(), v.end(), {});
EXPECT_TRUE(std::count(v.begin(), v.end(), 0) == v.size(), "a sequence is not filled properly by oneapi::dpl::fill with `unseq` policy");
}

{
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@danhoeflinger danhoeflinger Nov 18, 2025 •
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[nitpick] Remove extra unnecessary braces (this goes away if we use invoke_on_all_policies)

{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{6},{5},{4},{3},{7},{8},{2},{1},{4}};
oneapi::dpl::fill(oneapi::dpl::execution::par, v_custom.begin(), v_custom.end(), {});
EXPECT_TRUE(std::count(v_custom.begin(), v_custom.end(), TestUtils::DefaultInitializedToOne{}) == v_custom.size(),
"a sequence is not filled properly by oneapi::dpl::fill with `par` policy");
}
{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{6},{5},{4},{3},{7},{8},{2},{1},{4}};
oneapi::dpl::fill(oneapi::dpl::execution::par_unseq, v_custom.begin(), v_custom.end(), {});
EXPECT_TRUE(std::count(v_custom.begin(), v_custom.end(), TestUtils::DefaultInitializedToOne{}) == v_custom.size(),
"a sequence is not filled properly by oneapi::dpl::fill with `par_unseq` policy");
}
}
#if TEST_DPCPP_BACKEND_PRESENT
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
sycl::buffer<int> buf(v);
auto it = oneapi::dpl::fill(oneapi::dpl::execution::dpcpp_default, oneapi::dpl::begin(buf), oneapi::dpl::end(buf), {});
EXPECT_TRUE(std::count(v.begin(), v.end(), 0) == v.size(), "a sequence is not filled properly by oneapi::dpl::fill with `device_policy` policy");
#endif
}

void test_empty_list_initialization_for_fill_n()
{
constexpr std::size_t fill_number = 6;
{
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
auto it = oneapi::dpl::fill_n(oneapi::dpl::execution::seq, v.begin(), fill_number, {});
auto count = std::count(v.begin(), v.begin() + fill_number, 0);
EXPECT_TRUE(it == (v.begin() + fill_number), "an incorrect iterator returned from oneapi::dpl::fill_n with `seq` policy");
EXPECT_TRUE(count == fill_number, "a sequence is not filled properly by oneapi::dpl::fill_n with `seq` policy");
}
{
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
auto it = oneapi::dpl::fill_n(oneapi::dpl::execution::unseq, v.begin(), fill_number, {});
auto count = std::count(v.begin(), v.begin() + fill_number, 0);
EXPECT_TRUE(it == (v.begin() + fill_number), "an incorrect iterator returned from oneapi::dpl::fill_n with `unseq` policy");
EXPECT_TRUE(count == fill_number, "a sequence is not filled properly by oneapi::dpl::fill_n with `unseq` policy");
}

{
{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{6},{5},{4},{3},{7},{8},{2},{1},{4}};
auto it = oneapi::dpl::fill_n(oneapi::dpl::execution::par, v_custom.begin(), fill_number, {});
auto count = std::count(v_custom.begin(), v_custom.begin() + fill_number, TestUtils::DefaultInitializedToOne{1});
EXPECT_TRUE(it == (v_custom.begin() + fill_number), "an incorrect iterator returned from oneapi::dpl::fill_n with `par` policy");
EXPECT_TRUE(count == fill_number, "a sequence is not filled properly by oneapi::dpl::fill_n with `par` policy");
}
{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{6},{5},{4},{3},{7},{8},{2},{1},{4}};
auto it = oneapi::dpl::fill_n(oneapi::dpl::execution::par_unseq, v_custom.begin(), fill_number, {});
auto count = std::count(v_custom.begin(), v_custom.begin() + fill_number, TestUtils::DefaultInitializedToOne{1});
EXPECT_TRUE(it == (v_custom.begin() + fill_number), "an incorrect iterator returned from oneapi::dpl::fill_n with `par_unseq` policy");
EXPECT_TRUE(count == fill_number, "a sequence is not filled properly by oneapi::dpl::fill_n with `par_unseq` policy");
}
}
#if TEST_DPCPP_BACKEND_PRESENT
std::vector<int> v{3,6,5,4,3,7,8,0,2,4};
sycl::buffer<int> buf(v);
auto it = oneapi::dpl::fill_n(oneapi::dpl::execution::dpcpp_default, oneapi::dpl::begin(buf), fill_number, {});
auto count = std::count(v.begin(), v.begin() + fill_number, 0);
EXPECT_TRUE(it.get_idx() == fill_number, "an incorrect iterator returned from oneapi::dpl::fill_n with `device_policy` policy");
EXPECT_TRUE(count == fill_number, "a sequence is not filled properly by oneapi::dpl::fill_n with `device_policy` policy");
#endif
}

int
main()
{
Expand All @@ -108,5 +187,8 @@ main()
test_fill_by_type<float64_t>(n);
}

test_empty_list_initialization_for_fill();
test_empty_list_initialization_for_fill_n();

return done();
}
50 changes: 50 additions & 0 deletions test/parallel_api/algorithm/alg.modifying.operations/remove.pass.cpp
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Expand Up @@ -105,6 +105,54 @@ struct test_non_const
}
};

void test_empty_list_initialization()
{
{
std::vector<int> v{3,6,0,4,0,7,8,0,3,4};
std::vector<int> expected{3,6,4,7,8,3,4};
auto it = oneapi::dpl::remove(oneapi::dpl::execution::seq, v.begin(), v.end(), {});
EXPECT_TRUE(it == v.begin() + 7, "not all empty list-initialized values are properly removed by oneapi::dpl::remove with `seq` policy");
v.erase(it, v.end());
EXPECT_TRUE(v == expected, "wrong effect from calling oneapi::dpl::remove with empty list-initialized value and with `seq` policy");
}
{
std::vector<int> v{3,6,0,4,0,7,8,0,3,4};
std::vector<int> expected{3,6,4,7,8,3,4};
auto it = oneapi::dpl::remove(oneapi::dpl::execution::unseq, v.begin(), v.end(), {});
EXPECT_TRUE(it == v.begin() + 7, "not all empty list-initialized values are properly removed by oneapi::dpl::remove with `unseq` policy");
v.erase(it, v.end());
EXPECT_TRUE(v == expected, "wrong effect from calling oneapi::dpl::remove with empty list-initialized value and with `unseq` policy");
}

{
{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{1},{5},{1},{3},{1},{8},{2},{0},{1}};
std::vector<TestUtils::DefaultInitializedToOne> expected_custom{{3},{5},{3},{8},{2},{0}};
auto it = oneapi::dpl::remove(oneapi::dpl::execution::par, v_custom.begin(), v_custom.end(), {});
EXPECT_TRUE(it == v_custom.begin() + 6, "not all empty list-initialized values are properly removed by oneapi::dpl::remove with `par` policy");
v_custom.erase(it, v_custom.end());
EXPECT_TRUE(v_custom == expected_custom, "wrong effect from calling oneapi::dpl::remove with empty list-initialized value and with `par` policy");
}
{
std::vector<TestUtils::DefaultInitializedToOne> v_custom{{3},{1},{5},{1},{3},{1},{8},{2},{0},{1}};
std::vector<TestUtils::DefaultInitializedToOne> expected_custom{{3},{5},{3},{8},{2},{0}};
auto it = oneapi::dpl::remove(oneapi::dpl::execution::par_unseq, v_custom.begin(), v_custom.end(), {});
EXPECT_TRUE(it == v_custom.begin() + 6, "not all empty list-initialized values are properly removed by oneapi::dpl::remove with `par_unseq` policy");
v_custom.erase(it, v_custom.end());
EXPECT_TRUE(v_custom == expected_custom, "wrong effect from calling oneapi::dpl::remove with empty list-initialized value and with `par_unseq` policy");
}
}
#if TEST_DPCPP_BACKEND_PRESENT
std::vector<int> v{3,6,0,4,0,7,8,0,3,4};
std::vector<int> expected{3,6,4,7,8,3,4};
sycl::buffer<int> buf(v);
auto it = oneapi::dpl::remove(oneapi::dpl::execution::dpcpp_default, oneapi::dpl::begin(buf), oneapi::dpl::end(buf), {});
EXPECT_TRUE(it.get_idx() == 7, "not all empty list-initialized values are properly removed by oneapi::dpl::remove with `device_policy` policy");
v.erase(v.begin() + it.get_idx(), v.end());
EXPECT_TRUE(v == expected, "wrong effect from calling oneapi::dpl::remove with empty list-initialized value and with `device_policy` policy");
#endif
}

int
main()
{
Expand Down Expand Up @@ -133,5 +181,7 @@ main()
EXPECT_TRUE(MemoryChecker::alive_objects() == 0, "wrong effect from remove,remove_if: number of ctor and dtor calls is not equal");
#endif

test_empty_list_initialization();

return done();
}
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