From 4f889d45e62d79b4697e13b91178b88645aceec4 Mon Sep 17 00:00:00 2001
From: Sergey Kopienko <sergey.kopienko@intel.com>
Date: Wed, 14 Aug 2024 14:02:38 +0200
Subject: [PATCH] Avid temporary __future instances, directly created on stack

Signed-off-by: Sergey Kopienko <sergey.kopienko@intel.com>
---
 .../internal/async_impl/async_impl_hetero.h   | 28 +++++++++----------
 .../dpcpp/parallel_backend_sycl_utils.h       |  6 ++++
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/include/oneapi/dpl/internal/async_impl/async_impl_hetero.h b/include/oneapi/dpl/internal/async_impl/async_impl_hetero.h
index 1558919b20f..506287d09ad 100644
--- a/include/oneapi/dpl/internal/async_impl/async_impl_hetero.h
+++ b/include/oneapi/dpl/internal/async_impl/async_impl_hetero.h
@@ -65,11 +65,10 @@ __pattern_walk2_async(__hetero_tag<_BackendTag>, _ExecutionPolicy&& __exec, _For
     auto __keep2 = oneapi::dpl::__ranges::__get_sycl_range<__acc_mode2, _ForwardIterator2>();
     auto __buf2 = __keep2(__first2, __first2 + __n);
 
-    auto __future = oneapi::dpl::__par_backend_hetero::__parallel_for(
-        _BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec),
-        unseq_backend::walk_n<_ExecutionPolicy, _Function>{__f}, __n, __buf1.all_view(), __buf2.all_view());
-
-    return __future.__make_future(__first2 + __n);
+    return oneapi::dpl::__par_backend_hetero::__parallel_for(_BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec),
+                                                             unseq_backend::walk_n<_ExecutionPolicy, _Function>{__f},
+                                                             __n, __buf1.all_view(), __buf2.all_view())
+        .__make_future(__first2 + __n);
 }
 
 template <typename _BackendTag, typename _ExecutionPolicy, typename _ForwardIterator1, typename _ForwardIterator2,
@@ -91,12 +90,11 @@ __pattern_walk3_async(__hetero_tag<_BackendTag>, _ExecutionPolicy&& __exec, _For
         oneapi::dpl::__ranges::__get_sycl_range<__par_backend_hetero::access_mode::write, _ForwardIterator3>();
     auto __buf3 = __keep3(__first3, __first3 + __n);
 
-    auto __future =
-        oneapi::dpl::__par_backend_hetero::__parallel_for(_BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec),
-                                                          unseq_backend::walk_n<_ExecutionPolicy, _Function>{__f}, __n,
-                                                          __buf1.all_view(), __buf2.all_view(), __buf3.all_view());
-
-    return __future.__make_future(__first3 + __n);
+    return oneapi::dpl::__par_backend_hetero::__parallel_for(_BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec),
+                                                             unseq_backend::walk_n<_ExecutionPolicy, _Function>{__f},
+                                                             __n, __buf1.all_view(), __buf2.all_view(),
+                                                             __buf3.all_view())
+        .__make_future(__first3 + __n);
 }
 
 template <typename _BackendTag, typename _ExecutionPolicy, typename _ForwardIterator1, typename _ForwardIterator2,
@@ -201,10 +199,10 @@ __pattern_transform_scan_base_async(__hetero_tag<_BackendTag>, _ExecutionPolicy&
     auto __keep2 = oneapi::dpl::__ranges::__get_sycl_range<__par_backend_hetero::access_mode::write, _Iterator2>();
     auto __buf2 = __keep2(__result, __result + __n);
 
-    auto __res = oneapi::dpl::__par_backend_hetero::__parallel_transform_scan(
-        _BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec), __buf1.all_view(), __buf2.all_view(), __n, __unary_op,
-        __init, __binary_op, _Inclusive{});
-    return __res.__make_future(__result + __n);
+    return oneapi::dpl::__par_backend_hetero::__parallel_transform_scan(
+               _BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec), __buf1.all_view(), __buf2.all_view(), __n,
+               __unary_op, __init, __binary_op, _Inclusive{})
+        .__make_future(__result + __n);
 }
 
 template <typename _BackendTag, typename _ExecutionPolicy, typename _Iterator1, typename _Iterator2,
diff --git a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_utils.h b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_utils.h
index 37b25b2e257..9a66039e879 100644
--- a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_utils.h
+++ b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_utils.h
@@ -797,6 +797,12 @@ class __future : private std::tuple<_Args...>
     }
 };
 
+template <typename _TData>
+inline __make_future(sycl::event&& __event, _TData&& __data)
+{
+    return __future<sycl::event, _TData>(std::move(__event), std::forward<_TData>(__data));
+}
+
 // Invoke a callable and pass a compile-time integer based on a provided run-time integer.
 // The compile-time integer that will be provided to the callable is defined as the smallest
 // value in the integer_sequence not less than the run-time integer. For example: