Harden handling of default arch when loading

- Allow default arch
- Add missing redirection for top-level load of complex
- Add minimal testing

Author: serge-sans-paille

include/xsimd/arch/generic/xsimd_generic_memory.hpp

@@ -55,6 +55,10 @@ namespace xsimd {
     batch<T_out, A> load_aligned(T_in const* mem, convert<T_out> cvt, requires_arch<generic>) {
       return detail::load_aligned<A>(mem, cvt, A{}, detail::conversion_type<A, T_in, T_out>{});
     }
+    template<class A, class T>
+    batch<std::complex<T>, A> load_aligned(std::complex<T> const* mem, convert<std::complex<T>>, requires_arch<generic>) {
+      return batch<std::complex<T>, A>::load_aligned(mem);
+    }
 
     // load_unaligned
     namespace detail {
@@ -75,7 +79,10 @@ namespace xsimd {
     batch<T_out, A> load_unaligned(T_in const* mem, convert<T_out> cvt, requires_arch<generic>) {
       return detail::load_unaligned<A>(mem, cvt, generic{}, detail::conversion_type<A, T_in, T_out>{});
     }
-
+    template<class A, class T>
+    batch<std::complex<T>, A> load_unaligned(std::complex<T> const* mem, convert<std::complex<T>>, requires_arch<generic>) {
+      return batch<std::complex<T>, A>::load_unaligned(mem);
+    }
 
     // store
     template<class T, class A>

include/xsimd/types/xsimd_api.hpp

@@ -917,7 +917,7 @@ batch<From, A> load(From const* ptr, unaligned_mode) {
  * @param ptr the memory buffer to read
  * @return a new batch instance
  */
-template<class A/*=default_arch*/, class From>
+template<class A=default_arch, class From>
 batch<From, A> load_aligned(From const* ptr) {
   return kernel::load_aligned<A>(ptr, kernel::convert<From>{}, A{});
 }
@@ -930,7 +930,7 @@ batch<From, A> load_aligned(From const* ptr) {
  * @param ptr the memory buffer to read
  * @return a new batch instance
  */
-template<class A/*=default_arch*/, class From>
+template<class A=default_arch, class From>
 batch<From, A> load_unaligned(From const* ptr) {
   return kernel::load_unaligned<A>(ptr, kernel::convert<From>{}, A{});
 }

test/test_arch.cpp

@@ -87,6 +87,29 @@ TEST(arch, dispatcher)
 #endif
 }
 
+template<class T>
+static bool try_load() {
+  static_assert(std::is_same<xsimd::batch<T>, decltype(xsimd::load_aligned(std::declval<T*>()))>::value,
+                "loading the expected type");
+  static_assert(std::is_same<xsimd::batch<T>, decltype(xsimd::load_unaligned(std::declval<T*>()))>::value,
+                "loading the expected type");
+  return true;
+}
+
+template<class... Tys>
+void try_loads() {
+  (void)std::initializer_list<bool>{try_load<Tys>()...};
+}
+
+TEST(arch, default_load)
+{
+  // make sure load_aligned / load_unaligned work for the default arch and
+  // return the appropriate type.
+  using type_list = xsimd::mpl::type_list<short, int, long, float, double, std::complex<float>, std::complex<double>>;
+  try_loads<type_list>();
+
+}
+
 #ifdef XSIMD_ENABLE_FALLBACK
 // FIXME: this should be named scalar
 TEST(arch, scalar)