Add option to conditionally enable SIMD (#39)

Summary:
`-march=native` doesn't work for cross-compiling. Change to use `-march=armv8-a` for cross-compiling for mac ARM on mac Intel and add a CMake option to control whether to enable SIMD.

Pull Request resolved: #39

Test Plan: CI

Reviewed By: yutingye

Differential Revision: D59495638

Pulled By: jeongseok-meta

fbshipit-source-id: 17ea1cc647c2d8f69be12f0af352f513dcfa2658

CMakeLists.txt

@@ -28,6 +28,7 @@ include(cmake/mt_defs.cmake)
 #===============================================================================
 
 option(BUILD_SHARED_LIBS "Build as shared libraries" ON)
+option(MOMENTUM_ENABLE_SIMD "Enable building with SIMD instructions" ON)
 option(MOMENTUM_BUILD_IO_FBX "Build with IO FBX" OFF)
 option(MOMENTUM_BUILD_PYMOMENTUM "Build Python binding" OFF)
 option(MOMENTUM_BUILD_TESTING "Enable building tests" OFF)

cmake/mt_defs.cmake

@@ -145,12 +145,20 @@ function(mt_library)
     ${type} ${_ARG_PUBLIC_COMPILE_DEFINITIONS}
     PRIVATE ${_ARG_PRIVATE_COMPILE_DEFINITIONS}
   )
-  if(MSVC)
-    target_compile_options(${_ARG_NAME} ${type} "/arch:SSE2")
-    target_compile_options(${_ARG_NAME} ${type} "/arch:AVX")
-    target_compile_options(${_ARG_NAME} ${type} "/arch:AVX2")
-  else()
-    target_compile_options(${_ARG_NAME} ${type} -march=native)
+  if(MOMENTUM_ENABLE_SIMD)
+    if(MSVC)
+      target_compile_options(${_ARG_NAME} ${type} "/arch:SSE2")
+      target_compile_options(${_ARG_NAME} ${type} "/arch:AVX")
+      target_compile_options(${_ARG_NAME} ${type} "/arch:AVX2")
+    elseif(APPLE)
+      if(CMAKE_OSX_ARCHITECTURES MATCHES "arm64")
+        target_compile_options(${_ARG_NAME} ${type} -march=armv8-a)
+      else()
+        target_compile_options(${_ARG_NAME} ${type} -march=native)
+      endif()
+    else()
+      target_compile_options(${_ARG_NAME} ${type} -march=native)
+    endif()
   endif()
   target_compile_options(${_ARG_NAME}
     ${type} ${_ARG_PUBLIC_COMPILE_OPTIONS}