diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 6eb6bdd5c3..7d1467a73e 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -381,10 +381,16 @@ include(Packages/MSCG)
 include(Packages/COMPRESS)
 
 set(CMAKE_TUNE_FLAGS "${CMAKE_TUNE_DEFAULT}" CACHE STRING "Compiler specific optimization or instrumentation")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_TUNE_FLAGS}")
-if(CMAKE_Fortran_COMPILER)
-  set(CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} ${CMAKE_TUNE_FLAGS}")
-endif()
+separate_arguments(CMAKE_TUNE_FLAGS)
+include(CheckCXXCompilerFlag)
+foreach(_FLAG ${CMAKE_TUNE_FLAGS})
+  check_cxx_compiler_flag("${_FLAG}" COMPILER_SUPPORTS${_FLAG})
+  if(COMPILER_SUPPORTS${_FLAG})
+    target_compile_options(lammps PRIVATE ${_FLAG})
+  else()
+    message(WARNING "${_FLAG} found in CMAKE_TUNE_FLAGS, but not supported by the compiler, skipping")
+  endif()
+endforeach()
 ########################################################################
 # Basic system tests (standard libraries, headers, functions, types)   #
 ########################################################################
diff --git a/cmake/Modules/Packages/USER-INTEL.cmake b/cmake/Modules/Packages/USER-INTEL.cmake
index 5d23facee6..3d110b8c27 100644
--- a/cmake/Modules/Packages/USER-INTEL.cmake
+++ b/cmake/Modules/Packages/USER-INTEL.cmake
@@ -76,7 +76,7 @@ if(PKG_USER-INTEL)
     if(CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
       include(CheckCXXCompilerFlag)
       foreach(_FLAG -O2 -fp-model fast=2 -no-prec-div -qoverride-limits -qopt-zmm-usage=high -qno-offload -fno-alias -ansi-alias -restrict)
-        check_cxx_compiler_flag("${__FLAG}" COMPILER_SUPPORTS${_FLAG})
+        check_cxx_compiler_flag("${_FLAG}" COMPILER_SUPPORTS${_FLAG})
         if(COMPILER_SUPPORTS${_FLAG})
 	  target_compile_options(lammps PRIVATE ${_FLAG})
         endif()