Add -flto to compiler flags

fixes #12564

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6abd47f792b3842ddcab620b5cf3250e4b2122eb..5032229af9741f0aba0bb9855dfd3dbed392b6b3 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -259,6 +259,16 @@ if(NOT MSVC)
   endif()
 endif()
 
+check_cxx_compiler_flag("-flto" CXX_FLAG_LTO)
+
+if(CXX_FLAG_LTO)
+  set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_DEBUG} -flto")
+  set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_DEBUG} -flto")
+
+  set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_DEBUG} -flto")
+  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_DEBUG} -flto")
+endif()
+
 configure_file(config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config.h ESCAPE_QUOTES)
 
 install(