From 045c23906075127704b62b00ba3b711273b69be2 Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Sat, 29 Jun 2024 15:15:15 +0200
Subject: [PATCH] DPL Analysis: speedup prune_voids_pack

---
 Framework/Foundation/include/Framework/Pack.h | 41 ++++++++++++++++---
 .../test/test_FunctionalHelpers.cxx           |  3 ++
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/Framework/Foundation/include/Framework/Pack.h b/Framework/Foundation/include/Framework/Pack.h
index e0593a6175b3a..89555ee45f20c 100644
--- a/Framework/Foundation/include/Framework/Pack.h
+++ b/Framework/Foundation/include/Framework/Pack.h
@@ -115,14 +115,45 @@ consteval auto prune_voids_pack(Result result, pack<>)
   return result;
 }
 
+// The first one is non void, but one of the others is void
 template <typename... Rs, typename T, typename... Ts>
+  requires(!std::is_void_v<T>)
 consteval auto prune_voids_pack(pack<Rs...> result, pack<T, Ts...>)
 {
-  if constexpr (std::is_void_v<T> == false) {
-    return prune_voids_pack(pack<Rs..., T>{}, pack<Ts...>{});
-  } else {
-    return prune_voids_pack(pack<Rs...>{}, pack<Ts...>{});
-  }
+  return prune_voids_pack(pack<Rs..., T>{}, pack<Ts...>{});
+}
+
+// The first one is void
+template <typename... Rs, typename V, typename... Ts>
+  requires(std::is_void_v<V>)
+consteval auto prune_voids_pack(pack<Rs...> result, pack<V, Ts...>)
+{
+  return prune_voids_pack(pack<Rs...>{}, pack<Ts...>{});
+}
+
+// The first one is non void, but one of the others is void
+template <typename... Rs, typename T1, typename T2, typename... Ts>
+  requires(!std::is_void_v<T1> && !std::is_void_v<T2>)
+consteval auto prune_voids_pack(pack<Rs...> result, pack<T1, T2, Ts...>)
+{
+  return prune_voids_pack(pack<Rs..., T1, T2>{}, pack<Ts...>{});
+}
+
+// Eats 4 types at the time
+template <typename... Rs, typename T1, typename T2, typename T3, typename T4, typename... Ts>
+  requires(!std::is_void_v<T1> && !std::is_void_v<T2> && !std::is_void_v<T3> && !std::is_void_v<T4>)
+consteval auto prune_voids_pack(pack<Rs...> result, pack<T1, T2, T3, T4, Ts...>)
+{
+  return prune_voids_pack(pack<Rs..., T1, T2, T3, T4>{}, pack<Ts...>{});
+}
+
+// Eats 8 types at the time
+template <typename... Rs, typename T1, typename T2, typename T3, typename T4,
+          typename T5, typename T6, typename T7, typename T8, typename... Ts>
+  requires(!std::is_void_v<T1> && !std::is_void_v<T2> && !std::is_void_v<T3> && !std::is_void_v<T4> && !std::is_void_v<T5> && !std::is_void_v<T6> && !std::is_void_v<T7> && !std::is_void_v<T8>)
+consteval auto prune_voids_pack(pack<Rs...> result, pack<T1, T2, T3, T4, T5, T6, T7, T8, Ts...>)
+{
+  return prune_voids_pack(pack<Rs..., T1, T2, T3, T4, T5, T6, T7, T8>{}, pack<Ts...>{});
 }
 
 /// Selects from the pack types that satisfy the Condition
diff --git a/Framework/Foundation/test/test_FunctionalHelpers.cxx b/Framework/Foundation/test/test_FunctionalHelpers.cxx
index 334da9ac1d5f5..895133ae6428d 100644
--- a/Framework/Foundation/test/test_FunctionalHelpers.cxx
+++ b/Framework/Foundation/test/test_FunctionalHelpers.cxx
@@ -32,6 +32,7 @@ TEST_CASE("TestOverride")
   static_assert(has_type<double>(pack<int, float>{}) == false, "double should not be in the pack");
   static_assert(has_type_v<int, pack<int, float>> == true, "int should be in the pack");
   static_assert(has_type_v<double, pack<int, float>> == false, "double should not be in the pack");
+  static_assert(std::is_same_v<decltype(prune_voids_pack({}, pack<int, int, int, int, int, int, int, int, void>{})), pack<int, int, int, int, int, int, int, int>>, "prune last void");
   static_assert(has_type_conditional_v<std::is_same, int, pack<int, float>> == true, "int should be in the pack");
   static_assert(has_type_conditional_v<std::is_same, double, pack<int, float>> == false, "double should not be in the pack");
 
@@ -42,6 +43,8 @@ TEST_CASE("TestOverride")
   static_assert(has_type_at_conditional<std::is_same, bool>(pack<int, float, double>()) == 3 + 1, "bool is not in the pack so the function returns size + 1");
 
   static_assert(std::is_same_v<selected_pack<is_int_t, int, float, char>, pack<int>>, "selector should select int");
+  static_assert(std::is_same_v<selected_pack<is_int_t, int, int, float, char>, pack<int, int>>, "selector should select int");
+  static_assert(std::is_same_v<selected_pack<is_int_t, float, int, int, float, char>, pack<int, int>>, "selector should select int");
   static_assert(std::is_same_v<selected_pack_multicondition<is_same_as_second_t, pack<int>, pack<int, float, char>>, pack<int>>, "multiselector should select int");
   static_assert(std::is_same_v<filtered_pack<is_int_t, int, float, char>, pack<float, char>>, "filter should remove int");
   static_assert(std::is_same_v<intersected_pack_t<pack<int, float, char>, pack<float, double>>, pack<float>>, "filter intersect two packs");