Fix regex flag parsing
Fix regex flag parsing

lijunsong/LambdaS5,brownplt/LambdaS5,lijunsong/LambdaS5,lijunsong/LambdaS5,logchi/LambdaS5,logchi/LambdaS5,brownplt/LambdaS5,brownplt/LambdaS5,logchi/LambdaS5