[SYCL][CMake] Add an option to enable IPO for runtime builds (#20548)

Author: sergey-semenov

sycl/CMakeLists.txt

@@ -11,6 +11,7 @@ option(SYCL_ADD_DEV_VERSION_POSTFIX "Adds -V postfix to version string" ON)
 option(SYCL_ENABLE_COVERAGE "Enables code coverage for runtime and unit tests" OFF)
 option(SYCL_ENABLE_STACK_PRINTING "Enables stack printing on crashes of SYCL applications" OFF)
 option(SYCL_LIB_WITH_DEBUG_SYMBOLS "Builds SYCL runtime libraries with debug symbols" OFF)
+option(SYCL_ENABLE_IPO "Builds SYCL runtime libraries with interprocedural optimization" OFF)
 
 if (NOT SYCL_COVERAGE_PATH)
   set(SYCL_COVERAGE_PATH "${CMAKE_CURRENT_BINARY_DIR}/profiles")

sycl/source/CMakeLists.txt

@@ -4,6 +4,7 @@
 #cmake_policy(SET CMP0057 NEW)
 #include(AddLLVM)
 include(CheckLinkerFlag)
+include(CheckIPOSupported)
 configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/version.rc.in
   ${CMAKE_CURRENT_BINARY_DIR}/version.rc
@@ -16,13 +17,24 @@ if (SYCL_ENABLE_XPTI_TRACING)
   include_directories(${LLVM_EXTERNAL_XPTI_SOURCE_DIR}/include)
 endif()
 
+if(SYCL_ENABLE_IPO)
+  check_ipo_supported(RESULT SYCL_USE_IPO)
+  if (NOT SYCL_USE_IPO)
+    message(WARNING "Interprocedural optimization is not supported by the compiler, disabling")
+  endif()
+endif()
+
 function(add_sycl_rt_library LIB_NAME LIB_OBJ_NAME)
   # Add an optional argument so we can get the library name to
   # link with for Windows Debug version
   cmake_parse_arguments(ARG "" "XPTI_LIB;IMPLIB_NAME" "COMPILE_OPTIONS;SOURCES" ${ARGN})
 
   add_library(${LIB_OBJ_NAME} OBJECT ${ARG_SOURCES})
 
+  if(SYCL_USE_IPO)
+    set_property(TARGET ${LIB_OBJ_NAME} PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
+  endif()
+
   # Common compilation step setup
 
   check_cxx_compiler_flag(-Winstantiation-after-specialization
@@ -79,6 +91,10 @@ function(add_sycl_rt_library LIB_NAME LIB_OBJ_NAME)
               $<TARGET_OBJECTS:${LIB_OBJ_NAME}>
               ${CMAKE_CURRENT_BINARY_DIR}/version.rc)
 
+  if(SYCL_USE_IPO)
+    set_property(TARGET ${LIB_NAME} PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
+  endif()
+
   find_package(Threads REQUIRED)
 
   target_link_libraries(${LIB_NAME}