diff --git a/CMakeLists.txt b/CMakeLists.txt
index fee94339c6bcbc8a6fd2280d9857314acf3b477e..3488680d698de0f9713e1bbbdb1a244ebd748c5d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -944,7 +944,7 @@ if ( WALBERLA_CXX_COMPILER_IS_MSVC )
     string(REPLACE "/Od" "/O2"   CMAKE_CXX_FLAGS_DEBUGOPTIMIZED ${CMAKE_CXX_FLAGS_DEBUGOPTIMIZED})
     string(REPLACE "/Ob0" "/Ob2" CMAKE_CXX_FLAGS_DEBUGOPTIMIZED ${CMAKE_CXX_FLAGS_DEBUGOPTIMIZED})
     string(REPLACE "/RTC1" ""    CMAKE_CXX_FLAGS_DEBUGOPTIMIZED ${CMAKE_CXX_FLAGS_DEBUGOPTIMIZED})
-elseif( WALBERLA_CXX_COMPILER_IS_GNU OR WALBERLA_CXX_COMPILER_IS_INTEL OR WALBERLA_CXX_COMPILER_IS_CLANG )
+elseif( WALBERLA_CXX_COMPILER_IS_GNU OR WALBERLA_CXX_COMPILER_IS_INTEL OR WALBERLA_CXX_COMPILER_IS_CLANG OR WALBERLA_CXX_COMPILER_IS_INTELLLVM )
    set( CMAKE_C_FLAGS_DEBUGOPTIMIZED   "${CMAKE_C_FLAGS_DEBUGOPTIMIZED} -O3" )
    set( CMAKE_CXX_FLAGS_DEBUGOPTIMIZED "${CMAKE_CXX_FLAGS_DEBUGOPTIMIZED} -O3" )
 endif()