diff --git a/math/vdt/tests/CMakeLists.txt b/math/vdt/tests/CMakeLists.txt
index 384dcfa079516..b66b180e00a23 100644
--- a/math/vdt/tests/CMakeLists.txt
+++ b/math/vdt/tests/CMakeLists.txt
@@ -1,16 +1,21 @@
 set (Libraries  Core Hist Gpad MathCore)
 set (testname stressVdt)
 
-if( "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND CLANG_MAJOR GREATER 3 AND CLANG_MINOR GREATER 8 )
-  set (ModernClang True)
+
+if( CMAKE_COMPILER_IS_GNUCXX AND GCC_MAJOR GREATER 3 AND GCC_MINOR GREATER 6 )
+  set (ModernGcc True)
 endif()
 
-set(additional_compile_flags "-D__extern_always_inline=inline -O3")
+if( "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND CLANG_MAJOR GREATER 2 AND CLANG_MINOR GREATER 3 )
+  set (ModernClang True)
+  # __extern_always_inline is not understood by clang as of version 3.5
+  set (alwaysInlineClang "-D__extern_always_inline=inline")
+endif()
 
-if( ModernClang )
-  set(additional_compile_flags "${additional_compile_flags} -funsafe-math-optimizations -fno-trapping-math -ffinite-math-only")
-else()
-  set(additional_compile_flags "${additional_compile_flags} -ffast-math")
+if( ModernGcc )
+   set(additional_compile_flags "-O3 -ffast-math")
+elseif(ModernClang)
+   set(additional_compile_flags "-O3 -funsafe-math-optimizations -fno-trapping-math -ffinite-math-only ${alwaysInlineClang} ")
 endif()
 
 ROOT_EXECUTABLE(${testname} ${testname}.cxx LIBRARIES ${Libraries} ADDITIONAL_COMPILE_FLAGS ${additional_compile_flags} )