Attempt to enable SIMD if possible

Signed-off-by: Juan Cruz Viotti <[email protected]>

cmake/noa/defaults.cmake

@@ -93,3 +93,38 @@ if(NOA_COMPILER_LLVM AND CMAKE_BUILD_TYPE STREQUAL "Release" AND NOT BUILD_SHARE
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -flto=full")
   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -flto=full")
 endif()
+
+# Attempt to enable SIMD (SSE/AVX/NEON)
+include(CheckCXXCompilerFlag)
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "x86|AMD64")
+  if(MSVC)
+    if(NOT CMAKE_CL_64)
+      message(STATUS "Enabling SSE2")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:SSE2")
+    endif()
+    check_cxx_compiler_flag("/arch:AVX2" COMPILER_SUPPORTS_AVX2)
+    if(COMPILER_SUPPORTS_AVX2)
+      message(STATUS "Enabling AVX2")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:AVX2")
+    endif()
+  else()
+    check_cxx_compiler_flag("-msse4.2" COMPILER_SUPPORTS_SSE42)
+    if(COMPILER_SUPPORTS_SSE42)
+      message(STATUS "Enabling SSE4.2")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.2")
+    endif()
+
+    check_cxx_compiler_flag("-mavx2" COMPILER_SUPPORTS_AVX2)
+    if(COMPILER_SUPPORTS_AVX2)
+      message(STATUS "Enabling AVX2")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx2")
+    endif()
+  endif()
+endif()
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64" AND NOT MSVC)
+  check_cxx_compiler_flag("-march=armv8-a+fp+simd" COMPILER_SUPPORTS_NEON)
+  if(COMPILER_SUPPORTS_NEON)
+    message(STATUS "Enabling NEON")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=armv8-a+fp+simd")
+  endif()
+endif()