Update CMakeLists.txt

Author: loganmc10

CMakeLists.txt

@@ -10,6 +10,21 @@ include_directories(../mupen64plus-core/src/api)
 add_definitions(-DM64P_PLUGIN_API)
 add_definitions(-DPARALLEL_INTEGRATION)
 
+# check for INTERPROCEDURAL_OPTIMIZATION support
+if((${CMAKE_VERSION} VERSION_EQUAL 3.9) OR (${CMAKE_VERSION} VERSION_GREATER 3.9))
+    cmake_policy(SET CMP0069 NEW)
+
+    include(CheckIPOSupported)
+    check_ipo_supported(RESULT ENABLE_IPO)
+    if(ENABLE_IPO)
+        message("Interprocedural optimizations enabled")
+    endif(ENABLE_IPO)
+endif()
+
+if(ENABLE_IPO AND (CMAKE_BUILD_TYPE STREQUAL "Release"))
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
+endif()
+
 if (CMAKE_COMPILER_IS_GNUCXX OR (${CMAKE_CXX_COMPILER_ID} MATCHES "Clang"))
     set(PARALLEL_RSP_CXX_FLAGS -Wall -Wextra -Wno-missing-field-initializers -Wno-empty-body -ffast-math -Wno-unused-parameter)
 elseif (MSVC)