diff --git a/test/maple_test/compare.py b/test/maple_test/compare.py
index fa7e40a13d15e73e12971703b7edf7519d070eaa..f47c283537a5a731653dbe339dcbe2fb71275c5c 100644
--- a/test/maple_test/compare.py
+++ b/test/maple_test/compare.py
@@ -84,8 +84,6 @@ def main():
                 )
         else:
             raise CompareError("Unsupport flag: {!r}".format(flag))
-        if not is_valid_pattern(pattern):
-            raise CompareError("Not valid pattern: {!r}".format(pattern))
 
         keywords = pattern_flag.split("-")
         match_func = gen_match_func(keywords)
@@ -172,6 +170,8 @@ def is_valid_pattern(pattern):
 
 def regex_match(content, line_map, pattern, start=0):
     pattern = r"\s+".join([word for word in pattern.split()])
+    if not is_valid_pattern(pattern):
+        raise CompareError("Not valid pattern: {!r}".format(pattern))
     matches = re.finditer(str(pattern), content, re.MULTILINE)
     end = 0
     for _, match in enumerate(matches, start=1):