diff --git a/common/cmake/clang.cmake b/common/cmake/clang.cmake
index 2666d1be8b..261ba52664 100644
--- a/common/cmake/clang.cmake
+++ b/common/cmake/clang.cmake
@@ -82,7 +82,10 @@ ELSE()
 
   OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." ON)
   OPTION(EMBREE_ADDRESS_SANITIZER "Enabled CLANG address sanitizer." OFF)
-  IF (EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+  IF(EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+    IF(CMAKE_CXX_FLAGS)
+      MESSAGE(WARNING "Ignoring CMAKE_CXX_FLAGS because EMBREE_IGNORE_CMAKE_CXX_FLAGS is enabled.")
+    ENDIF()
     SET(CMAKE_CXX_FLAGS "")
   ENDIF()
 
diff --git a/common/cmake/dpcpp.cmake b/common/cmake/dpcpp.cmake
index a15c179ab9..e9486d35a5 100644
--- a/common/cmake/dpcpp.cmake
+++ b/common/cmake/dpcpp.cmake
@@ -15,7 +15,10 @@ _SET_IF_EMPTY(FLAGS_AVX512 "-march=skx")
 
 IF (NOT WIN32)
   OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." ON)
-  IF (EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+  IF(EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+    IF(CMAKE_CXX_FLAGS)
+      MESSAGE(WARNING "Ignoring CMAKE_CXX_FLAGS because EMBREE_IGNORE_CMAKE_CXX_FLAGS is enabled.")
+    ENDIF()
     SET(CMAKE_CXX_FLAGS "")
   ENDIF()
 ENDIF()
diff --git a/common/cmake/gnu.cmake b/common/cmake/gnu.cmake
index 365212bdda..13cf28a61d 100644
--- a/common/cmake/gnu.cmake
+++ b/common/cmake/gnu.cmake
@@ -21,7 +21,10 @@ ELSE ()
 ENDIF ()
 
 OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." ON)
-IF (EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+IF(EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+  IF(CMAKE_CXX_FLAGS)
+    MESSAGE(WARNING "Ignoring CMAKE_CXX_FLAGS because EMBREE_IGNORE_CMAKE_CXX_FLAGS is enabled.")
+  ENDIF()
   SET(CMAKE_CXX_FLAGS "")
 ENDIF()
 
diff --git a/common/cmake/intel.cmake b/common/cmake/intel.cmake
index 2c8e86e6c5..609b83eb73 100644
--- a/common/cmake/intel.cmake
+++ b/common/cmake/intel.cmake
@@ -101,7 +101,10 @@ ELSE()
   _SET_IF_EMPTY(FLAGS_AVX512 "-xCORE-AVX512")
 
   OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." ON)
-  IF (EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+  IF(EMBREE_IGNORE_CMAKE_CXX_FLAGS)
+    IF(CMAKE_CXX_FLAGS)
+      MESSAGE(WARNING "Ignoring CMAKE_CXX_FLAGS because EMBREE_IGNORE_CMAKE_CXX_FLAGS is enabled.")
+    ENDIF()
     SET(CMAKE_CXX_FLAGS "")
   ENDIF()