cmake: Add option ENABLE_NATIVE_OPTIMIZATION

Author: OpenSauce04

CMakeLists.txt

@@ -90,6 +90,7 @@ option(USE_DISCORD_PRESENCE "Enables Discord Rich Presence" OFF)
 # Compile options
 CMAKE_DEPENDENT_OPTION(COMPILE_WITH_DWARF "Add DWARF debugging information" ${IS_DEBUG_BUILD} "MINGW" OFF)
 option(ENABLE_LTO "Enable link time optimization" ${DEFAULT_ENABLE_LTO})
+option(ENABLE_NATIVE_OPTIMIZATION "Enables processor-specific optimizations via -march=native" OFF)
 option(CITRA_USE_PRECOMPILED_HEADERS "Use precompiled headers" ON)
 option(CITRA_WARNINGS_AS_ERRORS "Enable warnings as errors" ON)
 
@@ -146,6 +147,22 @@ else()
     message(STATUS "LTO disabled")
 endif()
 
+# Check for march=native support
+# =======================================================================
+if (ENABLE_NATIVE_OPTIMIZATION)
+    include(CheckCCompilerFlag)
+    include(CheckCXXCompilerFlag)
+    CHECK_C_COMPILER_FLAG("-march=native" C_COMPILER_SUPPORTS_MARCH_NATIVE)
+    CHECK_CXX_COMPILER_FLAG("-march=native" CXX_COMPILER_SUPPORTS_MARCH_NATIVE)
+
+    if (C_COMPILER_SUPPORTS_MARCH_NATIVE)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=native")
+    endif()
+    if (CXX_COMPILER_SUPPORTS_MARCH_NATIVE)
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
+    endif()
+endif()
+
 # Sanity check : Check that all submodules are present
 # =======================================================================