From 271af70eb26cc0fa73fba8a69c24071a27ef081d Mon Sep 17 00:00:00 2001
From: MikeDvorskiy <mikhail.dvorskiy@intel.com>
Date: Thu, 28 Nov 2024 17:28:56 +0100
Subject: [PATCH] [oneDPL][ranges][merge]  support size limit for output; +
 __parallel_merge sycl pattern support

---
 include/oneapi/dpl/pstl/hetero/algorithm_ranges_impl_hetero.h   | 2 +-
 .../oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/oneapi/dpl/pstl/hetero/algorithm_ranges_impl_hetero.h b/include/oneapi/dpl/pstl/hetero/algorithm_ranges_impl_hetero.h
index b9cd154a04..8ab7042c66 100644
--- a/include/oneapi/dpl/pstl/hetero/algorithm_ranges_impl_hetero.h
+++ b/include/oneapi/dpl/pstl/hetero/algorithm_ranges_impl_hetero.h
@@ -54,7 +54,7 @@ template <typename _BackendTag, typename _ExecutionPolicy, typename _Function, t
 void
 __pattern_walk_n(__hetero_tag<_BackendTag>, _ExecutionPolicy&& __exec, _Function __f, _Ranges&&... __rngs)
 {
-    auto __n = oneapi::dpl::__ranges::__get_first_range_size(__rngs...);
+    auto __n = std::min({__rngs...});
     if (__n > 0)
     {
         oneapi::dpl::__par_backend_hetero::__parallel_for(_BackendTag{}, ::std::forward<_ExecutionPolicy>(__exec),
diff --git a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
index 753e32816a..b1ee74ca04 100644
--- a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
+++ b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
@@ -142,7 +142,7 @@ struct __parallel_merge_submitter<_IdType, __internal::__optional_kernel_name<_N
     {
         const _IdType __n1 = __rng1.size();
         const _IdType __n2 = __rng2.size();
-        const _IdType __n = __n1 + __n2;
+        const _IdType __n = std::min<_IdType>(__n_1 + __n_2, std::ranges::size(__rng3));
 
         assert(__n1 > 0 || __n2 > 0);