Address comments

Avoid `__builtin_popcountll` on ARMv7-A since it is entirely manual:
<https://godbolt.org/z/vdM4f4n9G>.

Author: onalante-ebay

include/xsimd/types/xsimd_bit.hpp …e/xsimd/arch/common/xsimd_common_bit.hppinclude/xsimd/types/xsimd_bit.hpp renamed to include/xsimd/arch/common/xsimd_common_bit.hpp include/xsimd/types/xsimd_bit.hpp renamed to include/xsimd/arch/common/xsimd_common_bit.hpp

@@ -12,7 +12,7 @@
 #ifndef XSIMD_COMMON_LOGICAL_HPP
 #define XSIMD_COMMON_LOGICAL_HPP
 
-#include "../../types/xsimd_bit.hpp"
+#include "./xsimd_common_bit.hpp"
 #include "./xsimd_common_details.hpp"
 
 #include <climits>

include/xsimd/arch/common/xsimd_common_logical.hpp

@@ -13,6 +13,7 @@
 #define XSIMD_COMMON_HPP
 
 #include "./common/xsimd_common_arithmetic.hpp"
+#include "./common/xsimd_common_bit.hpp"
 #include "./common/xsimd_common_cast.hpp"
 #include "./common/xsimd_common_complex.hpp"
 #include "./common/xsimd_common_logical.hpp"

include/xsimd/arch/xsimd_common.hpp

@@ -18,9 +18,9 @@
 #include <tuple>
 #include <type_traits>
 
-#include "../types/xsimd_bit.hpp"
 #include "../types/xsimd_neon_register.hpp"
 #include "../types/xsimd_utils.hpp"
+#include "./common/xsimd_common_bit.hpp"
 #include "./common/xsimd_common_cast.hpp"
 
 // Wrap intrinsics so we can pass them as function pointers
@@ -3362,36 +3362,12 @@ namespace xsimd
         /*********
          * count *
          *********/
-        template <class A, class T, detail::enable_sized_t<T, 1> = 0>
-        XSIMD_INLINE size_t count(batch_bool<T, A> const& self, requires_arch<neon>) noexcept
-        {
-            uint8x8_t narrowed = vshrn_n_u16(vreinterpretq_u16_u8(self), 4);
-            uint64_t result = vget_lane_u64(vreinterpret_u64_u8(narrowed), 0);
-            return xsimd::detail::popcount(result) / 4;
-        }
-
-        template <class A, class T, detail::enable_sized_t<T, 2> = 0>
-        XSIMD_INLINE size_t count(batch_bool<T, A> const& self, requires_arch<neon>) noexcept
-        {
-            uint8x8_t narrowed = vmovn_u16(self);
-            uint64_t result = vget_lane_u64(vreinterpret_u64_u8(narrowed), 0);
-            return xsimd::detail::popcount(result) / 8;
-        }
-
-        template <class A, class T, detail::enable_sized_t<T, 4> = 0>
-        XSIMD_INLINE size_t count(batch_bool<T, A> const& self, requires_arch<neon>) noexcept
-        {
-            uint16x4_t narrowed = vmovn_u32(self);
-            uint64_t result = vget_lane_u64(vreinterpret_u64_u16(narrowed), 0);
-            return xsimd::detail::popcount(result) / 16;
-        }
-
-        template <class A, class T, detail::enable_sized_t<T, 8> = 0>
+        template <class A, class T>
         XSIMD_INLINE size_t count(batch_bool<T, A> const& self, requires_arch<neon>) noexcept
         {
-            uint32x2_t narrowed = vmovn_u64(self);
-            uint64_t result = vget_lane_u64(vreinterpret_u64_u32(narrowed), 0);
-            return xsimd::detail::popcount(result) / 32;
+            uint8x16_t popcnts = vcntq_u8(bitwise_cast<uint8_t, T, A>(bitwise_cast<T, A>(self)));
+            uint64x2_t total = vpaddlq_u32(vpaddlq_u16(vpaddlq_u8(popcnts)));
+            return vget_lane_u64(vadd_u64(vgetq_low_u64(total), vgetq_high_u64(total)), 0) / (sizeof(T) * 8);
         }
 
 #define WRAP_MASK_OP(OP)                                                               \

include/xsimd/arch/xsimd_neon.hpp

@@ -76,7 +76,6 @@ namespace xsimd
 #else
 #include "types/xsimd_batch.hpp"
 #include "types/xsimd_batch_constant.hpp"
-#include "types/xsimd_bit.hpp"
 #include "types/xsimd_traits.hpp"
 
 // This include must come last