From d8096f0a3173a594c21cf6df1a993f39c5302ad1 Mon Sep 17 00:00:00 2001
From: Hari Hara Naveen S <harihara.sn@gmail.com>
Date: Tue, 8 Aug 2023 16:33:44 -0500
Subject: [PATCH] fixed cf

Signed-off-by: Hari Hara Naveen S <harihara.sn@gmail.com>

fixed expolicy not accepting par_unseq

Signed-off-by: Hari Hara Naveen S <harihara.sn@gmail.com>

cleanup changes

Signed-off-by: Hari Hara Naveen S <harihara.sn@gmail.com>

fixing missing concept header

Signed-off-by: Hari Hara Naveen S <harihara.sn@gmail.com>
---
 .../hpx/parallel/algorithms/detail/find.hpp   |  3 --
 .../hpx/parallel/unseq/simd_helpers.hpp       |  1 -
 .../include/hpx/parallel/util/loop.hpp        | 32 +++++++------------
 .../algorithms/util/test_simd_helpers.cpp     |  2 +-
 4 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/libs/core/algorithms/include/hpx/parallel/algorithms/detail/find.hpp b/libs/core/algorithms/include/hpx/parallel/algorithms/detail/find.hpp
index 8d80fe055f3c..30db28d9ac45 100644
--- a/libs/core/algorithms/include/hpx/parallel/algorithms/detail/find.hpp
+++ b/libs/core/algorithms/include/hpx/parallel/algorithms/detail/find.hpp
@@ -45,7 +45,6 @@ namespace hpx::parallel::detail {
             std::size_t base_idx, FwdIter part_begin, std::size_t part_count,
             Token& tok, T const& val, Proj&& proj)
         {
-            // TODO
             util::loop_idx_n<ExPolicy>(base_idx, part_begin, part_count, tok,
                 [&val, &proj, &tok](auto& v, std::size_t i) -> void {
                     if (HPX_INVOKE(proj, v) == val)
@@ -102,7 +101,6 @@ namespace hpx::parallel::detail {
             sequential_find_if_t<ExPolicy>, FwdIter part_begin,
             std::size_t part_count, Token& tok, F&& op, Proj&& proj)
         {
-            // TODO
             util::loop_n<std::decay_t<ExPolicy>>(part_begin, part_count, tok,
                 [&op, &tok, &proj](auto const& curr) {
                     if (HPX_INVOKE(op, HPX_INVOKE(proj, *curr)))
@@ -118,7 +116,6 @@ namespace hpx::parallel::detail {
             FwdIter part_begin, std::size_t part_count, Token& tok, F&& f,
             Proj&& proj)
         {
-            // TODO
             util::loop_idx_n<ExPolicy>(base_idx, part_begin, part_count, tok,
                 [&f, &proj, &tok](auto& v, std::size_t i) -> void {
                     if (HPX_INVOKE(f, HPX_INVOKE(proj, v)))
diff --git a/libs/core/algorithms/include/hpx/parallel/unseq/simd_helpers.hpp b/libs/core/algorithms/include/hpx/parallel/unseq/simd_helpers.hpp
index 62f3caa7658a..cf7bf8380e86 100644
--- a/libs/core/algorithms/include/hpx/parallel/unseq/simd_helpers.hpp
+++ b/libs/core/algorithms/include/hpx/parallel/unseq/simd_helpers.hpp
@@ -13,7 +13,6 @@
 #include <hpx/parallel/unseq/reduce_helpers.hpp>
 #include <hpx/type_support/construct_at.hpp>
 
-
 #include <algorithm>
 #include <cstddef>
 #include <cstdint>
diff --git a/libs/core/algorithms/include/hpx/parallel/util/loop.hpp b/libs/core/algorithms/include/hpx/parallel/util/loop.hpp
index e4af118ab774..a3bf3659cfb1 100644
--- a/libs/core/algorithms/include/hpx/parallel/util/loop.hpp
+++ b/libs/core/algorithms/include/hpx/parallel/util/loop.hpp
@@ -8,9 +8,9 @@
 
 #include <hpx/config.hpp>
 #include <hpx/assert.hpp>
+#include <hpx/concepts/concepts.hpp>
 #include <hpx/datastructures/tuple.hpp>
 #include <hpx/execution/traits/is_execution_policy.hpp>
-#include <hpx/executors/execution_policy.hpp>
 #include <hpx/functional/detail/invoke.hpp>
 #include <hpx/functional/detail/tag_fallback_invoke.hpp>
 #include <hpx/functional/invoke_result.hpp>
@@ -185,22 +185,12 @@ namespace hpx::parallel::util {
         }
     };
 
-    template <typename Begin, typename End, typename Pred,
-        HPX_CONCEPT_REQUIRES_(hpx::traits::is_random_access_iterator_v<Begin>)>
+    template <typename Begin, typename End, typename Pred, typename ExPolicy,
+        HPX_CONCEPT_REQUIRES_(hpx::traits::is_random_access_iterator_v<Begin>&&
+                hpx::is_unsequenced_execution_policy_v<ExPolicy>)>
     HPX_HOST_DEVICE HPX_FORCEINLINE Begin tag_invoke(
-        hpx::parallel::util::loop_pred_t<hpx::execution::unsequenced_policy>,
-        Begin HPX_RESTRICT begin, End HPX_RESTRICT end, Pred&& pred)
-    {
-        return unseq_first_n(
-            begin, std::distance(begin, end), HPX_FORWARD(Pred, pred));
-    }
-
-    template <typename Begin, typename End, typename Pred,
-        HPX_CONCEPT_REQUIRES_(hpx::traits::is_random_access_iterator_v<Begin>)>
-    HPX_HOST_DEVICE HPX_FORCEINLINE Begin tag_invoke(
-        hpx::parallel::util::loop_pred_t<
-            hpx::execution::unsequenced_task_policy>,
-        Begin HPX_RESTRICT begin, End HPX_RESTRICT end, Pred&& pred)
+        hpx::parallel::util::loop_pred_t<ExPolicy>, Begin HPX_RESTRICT begin,
+        End HPX_RESTRICT end, Pred&& pred)
     {
         return unseq_first_n(
             begin, std::distance(begin, end), HPX_FORWARD(Pred, pred));
@@ -1147,7 +1137,7 @@ namespace hpx::parallel::util {
 
         // Helper class to repeatedly call a function a given number of times
         // starting from a given iterator position.
-        template <typename IterCat, typename Dummy = void>
+        template <typename IterCat>
         struct loop_idx_n
         {
             ///////////////////////////////////////////////////////////////////
@@ -1185,8 +1175,8 @@ namespace hpx::parallel::util {
             }
         };
 
-        template <typename ExPolicy>
-        struct loop_idx_n<std::random_access_iterator_tag, ExPolicy>
+        template <>
+        struct loop_idx_n<std::random_access_iterator_tag>
         {
             ///////////////////////////////////////////////////////////////////
             // handle sequences of non-futures
@@ -1254,7 +1244,7 @@ namespace hpx::parallel::util {
             std::size_t base_idx, Iter it, std::size_t count, F&& f)
         {
             using cat = typename std::iterator_traits<Iter>::iterator_category;
-            return detail::loop_idx_n<cat, ExPolicy>::call(
+            return detail::loop_idx_n<cat>::call(
                 base_idx, it, count, HPX_FORWARD(F, f));
         }
 
@@ -1265,7 +1255,7 @@ namespace hpx::parallel::util {
             F&& f)
         {
             using cat = typename std::iterator_traits<Iter>::iterator_category;
-            return detail::loop_idx_n<cat, ExPolicy>::call(
+            return detail::loop_idx_n<cat>::call(
                 base_idx, it, count, tok, HPX_FORWARD(F, f));
         }
     };
diff --git a/libs/core/algorithms/tests/unit/algorithms/util/test_simd_helpers.cpp b/libs/core/algorithms/tests/unit/algorithms/util/test_simd_helpers.cpp
index e2927525257c..ab512b4c8316 100644
--- a/libs/core/algorithms/tests/unit/algorithms/util/test_simd_helpers.cpp
+++ b/libs/core/algorithms/tests/unit/algorithms/util/test_simd_helpers.cpp
@@ -23,7 +23,7 @@ void test_unseq_first_n1_dispatch2(std::size_t length, std::size_t first_index)
 {
     first_index = first_index % length;
 
-    std::vector<T> v(length, static_cast<T>(0));
+    std::vector<T> v(length);
     std::size_t i = 0;
 
     std::for_each(v.begin(), v.end(), [&](T& t) {