Full description of unavailable architecture

Author: serge-sans-paille

include/xsimd/config/xsimd_arch.hpp

@@ -111,6 +111,12 @@ namespace xsimd
 
     struct unavailable
     {
+        static constexpr bool supported() noexcept { return false; }
+        static constexpr bool available() noexcept { return false; }
+        static constexpr unsigned version() noexcept { return 0; }
+        static constexpr std::size_t alignment() noexcept { return 0; }
+        static constexpr bool requires_alignment() noexcept { return false; }
+        static constexpr char const* name() noexcept { return "<none>"; }
     };
 
     namespace detail

include/xsimd/config/xsimd_config.hpp

@@ -265,4 +265,8 @@
 
 #endif
 
+#if !XSIMD_WITH_SSE2 && !XSIMD_WITH_SSE3 && !XSIMD_WITH_SSSE3 && !XSIMD_WITH_SSE4_1 && !XSIMD_WITH_SSE4_2 && !XSIMD_WITH_AVX && !XSIMD_WITH_AVX2 && !XSIMD_WITH_FMA3 && !XSIMD_WITH_FMA5 && !XSIMD_WITH_AVX512F && !XSIMD_WITH_AVX512CD && !XSIMD_WITH_AVX512DQ && !XSIMD_WITH_AVX512BW && !XSIMD_WITH_NEON && !XSIMD_WITH_NEON64
+#define XSIMD_NO_SUPPORTED_ARCHITECTURE
+#endif
+
 #endif

include/xsimd/xsimd.hpp

@@ -18,12 +18,19 @@
 #define XSIMD_NO_DISCARD
 #endif
 
+#include "config/xsimd_config.hpp"
+
 #include "arch/xsimd_scalar.hpp"
 #include "memory/xsimd_aligned_allocator.hpp"
+
+#if defined(XSIMD_NO_SUPPORTED_ARCHITECTURE)
+// to type definition or anything appart from scalar definition and aligned allocator
+#else
 #include "types/xsimd_batch.hpp"
 #include "types/xsimd_batch_constant.hpp"
 #include "types/xsimd_traits.hpp"
 
 // This include must come last
 #include "types/xsimd_api.hpp"
 #endif
+#endif