diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -61,7 +61,7 @@
 RUN_LINE_RE = re.compile(r'^\s*(?://|[;#])\s*RUN:\s*(.*)$')
 CHECK_PREFIX_RE = re.compile(r'--?check-prefix(?:es)?[= ](\S+)')
 PREFIX_RE = re.compile('^[a-zA-Z0-9_-]+$')
-CHECK_RE = re.compile(r'^\s*[;#]\s*([^:]+?)(?:-NEXT|-NOT|-DAG|-LABEL|-SAME)?:')
+CHECK_RE = re.compile(r'^\s*(?://|[;#])\s*([^:]+?)(?:-NEXT|-NOT|-DAG|-LABEL|-SAME)?:')
 
 OPT_FUNCTION_RE = re.compile(
     r'^\s*define\s+(?:internal\s+)?[^@]*@(?P<func>[\w-]+?)\s*'
diff --git a/llvm/utils/update_cc_test_checks.py b/llvm/utils/update_cc_test_checks.py
--- a/llvm/utils/update_cc_test_checks.py
+++ b/llvm/utils/update_cc_test_checks.py
@@ -28,8 +28,6 @@
 
 ADVERT = '// NOTE: Assertions have been autogenerated by '
 
-CHECK_RE = re.compile(r'^\s*//\s*([^:]+?)(?:-NEXT|-NOT|-DAG|-LABEL)?:')
-
 SUBST = {
     '%clang': [],
     '%clang_cc1': ['-cc1'],
@@ -238,7 +236,7 @@
     input_lines = []
     with open(filename, 'r+') as f:
       for line in f:
-        m = CHECK_RE.match(line)
+        m = common.CHECK_RE.match(line)
         if not (m and m.group(1) in prefix_set) and line != '//\n':
           input_lines.append(line)
       f.seek(0)