diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -69,6 +69,9 @@
 
 if (COMPILER_RT_STANDALONE_BUILD)
   load_llvm_config()
+  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+  set(CMAKE_CXX_STANDARD_REQUIRED YES)
+  set(CMAKE_CXX_EXTENSIONS NO)
   if (TARGET intrinsics_gen)
     # Loading the llvm config causes this target to be imported so place it
     # under the appropriate folder in an IDE.
diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -81,7 +81,6 @@
 check_cxx_compiler_flag(-frtti               COMPILER_RT_HAS_FRTTI_FLAG)
 check_cxx_compiler_flag(-fno-rtti            COMPILER_RT_HAS_FNO_RTTI_FLAG)
 check_cxx_compiler_flag("-Werror -fno-function-sections" COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG)
-check_cxx_compiler_flag(-std=c++17           COMPILER_RT_HAS_STD_CXX17_FLAG)
 check_cxx_compiler_flag(-ftls-model=initial-exec COMPILER_RT_HAS_FTLS_MODEL_INITIAL_EXEC)
 check_cxx_compiler_flag(-fno-lto             COMPILER_RT_HAS_FNO_LTO_FLAG)
 check_cxx_compiler_flag(-fno-profile-generate COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)