diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -24,7 +24,6 @@
 set(LIBCXX_BINARY_INCLUDE_DIR "${LIBCXX_BINARY_DIR}/include/c++build")
 
 include(GNUInstallDirs)
-include(WarningFlags)
 
 # Require out of source build.
 include(MacroEnsureOutOfSourceBuild)
@@ -840,6 +839,8 @@
 endif()
 
 # Setup all common build flags =================================================
+include(LTO)
+include(WarningFlags)
 function(cxx_add_common_build_flags target)
   cxx_add_basic_build_flags(${target})
   cxx_add_warning_flags(${target} ${LIBCXX_ENABLE_WERROR} ${LIBCXX_ENABLE_PEDANTIC})
@@ -848,6 +849,7 @@
   cxx_add_rtti_flags(${target})
   cxx_add_module_flags(${target})
   cxx_link_system_libraries(${target})
+  cxx_enable_lto(${target})
 endfunction()
 
 #===============================================================================
diff --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
--- a/libcxxabi/src/CMakeLists.txt
+++ b/libcxxabi/src/CMakeLists.txt
@@ -154,11 +154,13 @@
   string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
 endif()
 
+include(LTO)
 include(WarningFlags)
 
 # Build the shared library.
 add_library(cxxabi_shared_objects OBJECT EXCLUDE_FROM_ALL ${LIBCXXABI_SOURCES} ${LIBCXXABI_HEADERS})
 cxx_add_warning_flags(cxxabi_shared_objects ${LIBCXXABI_ENABLE_WERROR} ${LIBCXXABI_ENABLE_PEDANTIC})
+cxx_enable_lto(cxxabi_shared_objects)
 if (LIBCXXABI_USE_LLVM_UNWINDER)
   if (LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY)
     target_link_libraries(cxxabi_shared_objects PUBLIC unwind_shared_objects) # propagate usage requirements
@@ -243,6 +245,7 @@
 # Build the static library.
 add_library(cxxabi_static_objects OBJECT EXCLUDE_FROM_ALL ${LIBCXXABI_SOURCES} ${LIBCXXABI_HEADERS})
 cxx_add_warning_flags(cxxabi_static_objects ${LIBCXXABI_ENABLE_WERROR} ${LIBCXXABI_ENABLE_PEDANTIC})
+cxx_enable_lto(cxxabi_static_objects)
 if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY)
   target_link_libraries(cxxabi_static_objects PUBLIC unwind_static_objects) # propagate usage requirements
   target_sources(cxxabi_static_objects PUBLIC $<TARGET_OBJECTS:unwind_static_objects>)
diff --git a/runtimes/cmake/Modules/LTO.cmake b/runtimes/cmake/Modules/LTO.cmake
new file mode 100644
--- /dev/null
+++ b/runtimes/cmake/Modules/LTO.cmake
@@ -0,0 +1,8 @@
+include(CheckIPOSupported)
+check_ipo_supported(RESULT _ipo_supported LANGUAGES C CXX)
+
+function(cxx_enable_lto target)
+  if (_ipo_supported)
+    set_property(TARGET ${target} PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
+  endif()
+endfunction()