enable if both compiler and hardware support this

CMakeLists.txt

@@ -74,7 +74,11 @@ add_compile_definitions(ALP_CMAKE_SOURCE_DIR="${CMAKE_CURRENT_SOURCE_DIR}")
 include_directories(include)
 
 # Src: -----------------------------------------------------------------------------------------------------------------
-add_subdirectory(src)
+if (TRUE)
+    message("---------------------------------------------------------------------------------------------------------")
+    message("-- ALP: build library:")
+    add_subdirectory(src)
+endif ()
 
 # Data: ----------------------------------------------------------------------------------------------------------------
 if (ALP_BUILD_TESTING OR ALP_BUILD_PUBLICATION OR ALP_BUILD_BENCHMARKING)

src/CMakeLists.txt

@@ -1,14 +1,33 @@
-# Detect AVX512 support
+# Detect hardware AVX-512 support
 include(CheckCXXCompilerFlag)
 
+# Step 1: Check compiler support for AVX-512
 check_cxx_compiler_flag("-mavx512dq" COMPILER_SUPPORTS_AVX512)
 
-if(COMPILER_SUPPORTS_AVX512)
-    message(STATUS "AVX512 support detected. Adding AVX512 flag for ALP library.")
-    set(AVX512_FLAG "-mavx512dq")
-else()
-    message(STATUS "AVX512 support not detected.")
-endif()
+if (COMPILER_SUPPORTS_AVX512)
+    message(STATUS "Compiler supports AVX512.")
+
+    # Step 2: Create a test program for AVX-512
+    file(WRITE "${CMAKE_BINARY_DIR}/check_avx512.cpp"
+            "#include <immintrin.h>
+        int main() {
+            __m512i x = _mm512_set1_epi32(1); // AVX-512 instruction
+            return _mm512_reduce_add_epi32(x);
+        }")
+
+    # Step 3: Try to compile and run the program
+    try_compile(HAS_AVX512_SUPPORT "${CMAKE_BINARY_DIR}" "${CMAKE_BINARY_DIR}/check_avx512.cpp"
+            CMAKE_FLAGS "-DCMAKE_CXX_FLAGS=-mavx512dq")
+
+    if (HAS_AVX512_SUPPORT)
+        message(STATUS "Hardware supports AVX-512. Adding AVX-512 flags.")
+        set(AVX512_FLAG "-mavx512dq")
+    else ()
+        message(STATUS "Hardware does not support AVX-512.")
+    endif ()
+else ()
+    message(STATUS "Compiler does not support AVX-512.")
+endif ()
 
 # Define the library
 add_library(ALP SHARED
@@ -19,7 +38,7 @@ add_library(ALP SHARED
         fastlanes_unffor.cpp
         )
 
-# Add AVX512 flag if supported
-if(AVX512_FLAG)
+# Add AVX-512 flag if supported
+if (AVX512_FLAG)
     target_compile_options(ALP PUBLIC ${AVX512_FLAG})
-endif()
+endif ()