Add is_only_from_lo/hi

Author: AntoinePrv

include/xsimd/arch/common/xsimd_common_swizzle.hpp

@@ -16,6 +16,8 @@
 #include <cstdint>
 #include <type_traits>
 
+#include "../../config/xsimd_inline.hpp"
+
 namespace xsimd
 {
     template <typename T, class A, T... Values>
@@ -80,6 +82,52 @@ namespace xsimd
                     && dup_hi_impl<I + 1, N, T, Vs...>();
             }
 
+            // ────────────────────────────────────────────────────────────────────────
+            // only_from_lo
+            template <typename T, T Size, T First, T... Vals>
+            struct only_from_lo_impl;
+
+            template <typename T, T Size, T Last>
+            struct only_from_lo_impl<T, Size, Last>
+            {
+                static constexpr bool value = (Last < (Size / 2));
+            };
+
+            template <typename T, T Size, T First, T... Vals>
+            struct only_from_lo_impl
+            {
+                static constexpr bool value = (First < (Size / 2)) && only_from_lo_impl<T, Size, Vals...>::value;
+            };
+
+            template <typename T, T... Vals>
+            constexpr bool is_only_from_lo()
+            {
+                return only_from_lo_impl<T, sizeof...(Vals), Vals...>::value;
+            };
+
+            // ────────────────────────────────────────────────────────────────────────
+            // only_from_hi
+            template <typename T, T Size, T First, T... Vals>
+            struct only_from_hi_impl;
+
+            template <typename T, T Size, T Last>
+            struct only_from_hi_impl<T, Size, Last>
+            {
+                static constexpr bool value = (Last >= (Size / 2));
+            };
+
+            template <typename T, T Size, T First, T... Vals>
+            struct only_from_hi_impl
+            {
+                static constexpr bool value = (First >= (Size / 2)) && only_from_hi_impl<T, Size, Vals...>::value;
+            };
+
+            template <typename T, T... Vals>
+            constexpr bool is_only_from_hi()
+            {
+                return only_from_hi_impl<T, sizeof...(Vals), Vals...>::value;
+            };
+
             // ────────────────────────────────────────────────────────────────────────
             //  1) helper to get the I-th value from the Vs pack
             template <std::size_t I, uint32_t Head, uint32_t... Tail>
@@ -118,6 +166,7 @@ namespace xsimd
                 static_assert(sizeof...(Vs) >= 1, "Need at least one lane");
                 return cross_impl<0, sizeof...(Vs), sizeof...(Vs) / 2, Vs...>::value;
             }
+
             template <typename T, T... Vs>
             XSIMD_INLINE constexpr bool is_identity() noexcept { return detail::identity_impl<0, T, Vs...>(); }
             template <typename T, T... Vs>
@@ -131,6 +180,10 @@ namespace xsimd
             template <typename T, class A, T... Vs>
             XSIMD_INLINE constexpr bool is_dup_hi(batch_constant<T, A, Vs...>) noexcept { return is_dup_hi<T, Vs...>(); }
             template <typename T, class A, T... Vs>
+            XSIMD_INLINE constexpr bool is_only_from_lo(batch_constant<T, A, Vs...>) noexcept { return detail::is_only_from_lo<T, Vs...>(); }
+            template <typename T, class A, T... Vs>
+            XSIMD_INLINE constexpr bool is_only_from_hi(batch_constant<T, A, Vs...>) noexcept { return detail::is_only_from_hi<T, Vs...>(); }
+            template <typename T, class A, T... Vs>
             XSIMD_INLINE constexpr bool is_cross_lane(batch_constant<T, A, Vs...>) noexcept { return detail::is_cross_lane<Vs...>(); }
 
         } // namespace detail

include/xsimd/arch/xsimd_common_fwd.hpp

@@ -65,6 +65,10 @@ namespace xsimd
             XSIMD_INLINE constexpr bool is_dup_hi(batch_constant<T, A, Vs...>) noexcept;
             template <typename T, class A, T... Vs>
             XSIMD_INLINE constexpr bool is_cross_lane(batch_constant<T, A, Vs...>) noexcept;
+            template <typename T, class A, T... Vs>
+            XSIMD_INLINE constexpr bool is_only_from_lo(batch_constant<T, A, Vs...>) noexcept;
+            template <typename T, class A, T... Vs>
+            XSIMD_INLINE constexpr bool is_only_from_hi(batch_constant<T, A, Vs...>) noexcept;
 
         }
     }

test/test_batch_manip.cpp

@@ -34,6 +34,12 @@ namespace xsimd
             // 8-lane dup-hi (repeat 4..7 twice)
             static_assert(is_dup_hi<std::uint32_t, 4, 5, 6, 7, 4, 5, 6, 7>(), "dup_hi failed");
             static_assert(!is_dup_lo<std::uint32_t, 4, 5, 6, 7, 4, 5, 6, 7>(), "dup_lo on dup_hi");
+            // 8-lane is-only-from-hi (repeat 4..7 twice)
+            static_assert(is_only_from_hi<std::uint32_t, 4, 5, 6, 7, 7, 7, 7, 7>(), "only_from_hi on hi");
+            static_assert(!is_only_from_hi<std::uint32_t, 4, 5, 6, 7, 7, 1, 7, 7>(), "only_from_hi failed");
+            // 8-lane is-only-from-lo (repeat 4..7 twice)
+            static_assert(is_only_from_lo<std::uint32_t, 0, 1, 2, 3, 3, 2, 1, 0>(), "only_from_lo on lo");
+            static_assert(!is_only_from_lo<std::uint32_t, 0, 1, 2, 7, 3, 2, 1, 0>(), "only_from_lo failed");
             // ────────────────────────────────────────────────────────────────────────
             //  4-lane identity
             static_assert(is_identity<std::uint32_t, 0, 1, 2, 3>(), "4-lane identity failed");