diff --git a/Modules/CMakeCheckCompilerFlagCommonPatterns.cmake b/Modules/CMakeCheckCompilerFlagCommonPatterns.cmake
index 3141d60..32dacbd 100644
--- a/Modules/CMakeCheckCompilerFlagCommonPatterns.cmake
+++ b/Modules/CMakeCheckCompilerFlagCommonPatterns.cmake
@@ -23,6 +23,8 @@ macro (CHECK_COMPILER_FLAG_COMMON_PATTERNS _VAR)
    set(${_VAR}
      FAIL_REGEX "[Uu]nrecogni[sz]ed .*option"               # GNU, NAG
      FAIL_REGEX "unknown .*option"                          # Clang
+     FAIL_REGEX "optimization flag .* not supported"        # Clang
+     FAIL_REGEX "argument unused during compilation:"       # Clang
      FAIL_REGEX "ignoring unknown option"                   # MSVC, Intel
      FAIL_REGEX "warning D9002"                             # MSVC, any lang
      FAIL_REGEX "option.*not supported"                     # Intel