diff --git a/llvm/utils/lit/lit/BooleanExpression.py b/llvm/utils/lit/lit/BooleanExpression.py
--- a/llvm/utils/lit/lit/BooleanExpression.py
+++ b/llvm/utils/lit/lit/BooleanExpression.py
@@ -79,9 +79,10 @@
             raise ValueError("expected: %s\nhave: %s" %
                              (self.quote(t), self.quote(self.token)))
 
-    def isIdentifier(self, t):
-        if (t is BooleanExpression.END or t == '&&' or t == '||' or
-            t == '!' or t == '(' or t == ')'):
+    @staticmethod
+    def isIdentifier(token):
+        if (token is BooleanExpression.END or token == '&&' or token == '||' or
+            token == '!' or token == '(' or token == ')'):
             return False
         return True
 
@@ -92,7 +93,7 @@
         elif self.accept('('):
             self.parseOR()
             self.expect(')')
-        elif not self.isIdentifier(self.token):
+        elif not BooleanExpression.isIdentifier(self.token):
             raise ValueError("expected: '!' or '(' or identifier\nhave: %s" %
                              self.quote(self.token))
         else:
@@ -191,7 +192,7 @@
                            "actual error was:\n%s\n" +
                            "expected error was:\n%s\n") % (expr, e, error))
         except BaseException as e:
-            self.fail(("expression %r caused the wrong exception; actual " + 
+            self.fail(("expression %r caused the wrong exception; actual " +
                       "exception was: \n%r") % (expr, e))
 
     def test_errors(self):
diff --git a/llvm/utils/lit/lit/Test.py b/llvm/utils/lit/lit/Test.py
--- a/llvm/utils/lit/lit/Test.py
+++ b/llvm/utils/lit/lit/Test.py
@@ -1,3 +1,4 @@
+import itertools
 import os
 from xml.sax.saxutils import quoteattr
 from json import JSONEncoder
@@ -161,7 +162,7 @@
         addMicroResult(microResult)
 
         Attach a micro-test result to the test result, with the given name and
-        result.  It is an error to attempt to attach a micro-test with the 
+        result.  It is an error to attempt to attach a micro-test with the
         same name multiple times.
 
         Each micro-test result must be an instance of the Result class.
@@ -358,6 +359,26 @@
         except ValueError as e:
             raise ValueError('Error in UNSUPPORTED list:\n%s' % str(e))
 
+    def getUsedFeatures(self):
+        """
+        getUsedFeatures() -> list of strings
+
+        Returns a list of all features appearing in XFAIL, UNSUPPORTED and
+        REQUIRES annotations for this test.
+        """
+        import lit.TestRunner
+        parsed = lit.TestRunner._parseKeywords(self.getSourcePath(), require_script=False)
+        feature_keywords = ('UNSUPPORTED:', 'REQUIRES:', 'XFAIL:')
+        boolean_expressions = itertools.chain.from_iterable(
+            parsed[k] or [] for k in feature_keywords
+        )
+        tokens = itertools.chain.from_iterable(
+            BooleanExpression.tokenize(expr) for expr in
+                boolean_expressions if expr != '*'
+        )
+        identifiers = set(filter(BooleanExpression.isIdentifier, tokens))
+        return identifiers
+
     def isEarlyTest(self):
         """
         isEarlyTest() -> bool
@@ -376,7 +397,7 @@
         safe_name = self.suite.name.replace(".","-")
 
         if safe_test_path:
-            class_name = safe_name + "." + "/".join(safe_test_path) 
+            class_name = safe_name + "." + "/".join(safe_test_path)
         else:
             class_name = safe_name + "." + safe_name
         class_name = quoteattr(class_name)
diff --git a/llvm/utils/lit/lit/TestRunner.py b/llvm/utils/lit/lit/TestRunner.py
--- a/llvm/utils/lit/lit/TestRunner.py
+++ b/llvm/utils/lit/lit/TestRunner.py
@@ -1373,31 +1373,26 @@
                 BooleanExpression.evaluate(s, [])
         return output
 
-def parseIntegratedTestScript(test, additional_parsers=[],
-                              require_script=True):
-    """parseIntegratedTestScript - Scan an LLVM/Clang style integrated test
-    script and extract the lines to 'RUN' as well as 'XFAIL', 'REQUIRES',
-    'UNSUPPORTED' and 'ALLOW_RETRIES' information.
 
-    If additional parsers are specified then the test is also scanned for the
-    keywords they specify and all matches are passed to the custom parser.
+def _parseKeywords(sourcepath, additional_parsers=[],
+                   require_script=True):
+    """_parseKeywords
 
-    If 'require_script' is False an empty script
-    may be returned. This can be used for test formats where the actual script
-    is optional or ignored.
-    """
+    Scan an LLVM/Clang style integrated test script and extract all the lines
+    pertaining to a special parser. This includes 'RUN', 'XFAIL', 'REQUIRES',
+    'UNSUPPORTED' and 'ALLOW_RETRIES', as well as other specified custom
+    parsers.
 
+    Returns a dictionary mapping each custom parser to its value after
+    parsing the test.
+    """
     # Install the built-in keyword parsers.
     script = []
     builtin_parsers = [
-        IntegratedTestKeywordParser('RUN:', ParserKind.COMMAND,
-                                    initial_value=script),
-        IntegratedTestKeywordParser('XFAIL:', ParserKind.BOOLEAN_EXPR,
-                                    initial_value=test.xfails),
-        IntegratedTestKeywordParser('REQUIRES:', ParserKind.BOOLEAN_EXPR,
-                                    initial_value=test.requires),
-        IntegratedTestKeywordParser('UNSUPPORTED:', ParserKind.BOOLEAN_EXPR,
-                                    initial_value=test.unsupported),
+        IntegratedTestKeywordParser('RUN:', ParserKind.COMMAND, initial_value=script),
+        IntegratedTestKeywordParser('XFAIL:', ParserKind.BOOLEAN_EXPR),
+        IntegratedTestKeywordParser('REQUIRES:', ParserKind.BOOLEAN_EXPR),
+        IntegratedTestKeywordParser('UNSUPPORTED:', ParserKind.BOOLEAN_EXPR),
         IntegratedTestKeywordParser('ALLOW_RETRIES:', ParserKind.INTEGER),
         IntegratedTestKeywordParser('END.', ParserKind.TAG)
     ]
@@ -1414,7 +1409,6 @@
         keyword_parsers[parser.keyword] = parser
 
     # Collect the test lines from the script.
-    sourcepath = test.getSourcePath()
     for line_number, command_type, ln in \
             parseIntegratedTestScriptCommands(sourcepath,
                                               keyword_parsers.keys()):
@@ -1441,6 +1435,37 @@
         if value and value[-1][-1] == '\\':
             raise ValueError("Test has unterminated %s lines (with '\\')" % key)
 
+    # Make sure there's at most one ALLOW_RETRIES: line
+    allowed_retries = keyword_parsers['ALLOW_RETRIES:'].getValue()
+    if allowed_retries and len(allowed_retries) > 1:
+        return lit.Test.Result(Test.UNRESOLVED,
+                               "Test has more than one ALLOW_RETRIES lines")
+
+    return {p.keyword: p.getValue() for p in keyword_parsers.values()}
+
+
+def parseIntegratedTestScript(test, additional_parsers=[],
+                              require_script=True):
+    """parseIntegratedTestScript - Scan an LLVM/Clang style integrated test
+    script and extract the lines to 'RUN' as well as 'XFAIL', 'REQUIRES',
+    'UNSUPPORTED' and 'ALLOW_RETRIES' information into the given test.
+
+    If additional parsers are specified then the test is also scanned for the
+    keywords they specify and all matches are passed to the custom parser.
+
+    If 'require_script' is False an empty script
+    may be returned. This can be used for test formats where the actual script
+    is optional or ignored.
+    """
+    # Parse the test sources and extract test properties
+    parsed = _parseKeywords(test.getSourcePath(), additional_parsers, require_script)
+    script = parsed['RUN:'] or []
+    test.xfails = parsed['XFAIL:'] or []
+    test.requires = parsed['REQUIRES:'] or []
+    test.unsupported = parsed['UNSUPPORTED:'] or []
+    if parsed['ALLOW_RETRIES:']:
+        test.allowed_retries = parsed['ALLOW_RETRIES:'][0]
+
     # Enforce REQUIRES:
     missing_required_features = test.getMissingRequiredFeatures()
     if missing_required_features:
@@ -1458,14 +1483,6 @@
             "Test does not support the following features "
             "and/or targets: %s" % msg)
 
-    # Handle ALLOW_RETRIES:
-    allowed_retries = keyword_parsers['ALLOW_RETRIES:'].getValue()
-    if allowed_retries:
-        if len(allowed_retries) > 1:
-            return lit.Test.Result(Test.UNRESOLVED,
-                                   "Test has more than one ALLOW_RETRIES lines")
-        test.allowed_retries = allowed_retries[0]
-
     # Enforce limit_to_features.
     if not test.isWithinFeatureLimits():
         msg = ', '.join(test.config.limit_to_features)
diff --git a/llvm/utils/lit/lit/cl_arguments.py b/llvm/utils/lit/lit/cl_arguments.py
--- a/llvm/utils/lit/lit/cl_arguments.py
+++ b/llvm/utils/lit/lit/cl_arguments.py
@@ -156,6 +156,9 @@
     debug_group.add_argument("--show-tests",
             help="Show all discovered tests and exit",
             action="store_true")
+    debug_group.add_argument("--show-used-features",
+            help="Show all features used in the test suite (in XFAIL, UNSUPPORTED and REQUIRES) and exit",
+            action="store_true")
 
     # LIT is special: environment variables override command line arguments.
     env_args = shlex.split(os.environ.get("LIT_OPTS", ""))
diff --git a/llvm/utils/lit/lit/main.py b/llvm/utils/lit/lit/main.py
--- a/llvm/utils/lit/lit/main.py
+++ b/llvm/utils/lit/lit/main.py
@@ -4,6 +4,7 @@
 See lit.pod for more information.
 """
 
+import itertools
 import os
 import platform
 import sys
@@ -46,6 +47,11 @@
         print_discovered(discovered_tests, opts.show_suites, opts.show_tests)
         sys.exit(0)
 
+    if opts.show_used_features:
+        features = set(itertools.chain.from_iterable(t.getUsedFeatures() for t in discovered_tests))
+        print(' '.join(sorted(features)))
+        sys.exit(0)
+
     # Command line overrides configuration for maxIndividualTestTime.
     if opts.maxIndividualTestTime is not None:  # `not None` is important (default: 0)
         if opts.maxIndividualTestTime != lit_config.maxIndividualTestTime:
@@ -131,7 +137,6 @@
     tests.sort(key=lambda t: (t.suite.name, t.suite, t.path_in_suite))
 
     if show_suites:
-        import itertools
         tests_by_suite = itertools.groupby(tests, lambda t: t.suite)
         print('-- Test Suites --')
         for suite, suite_iter in tests_by_suite:
diff --git a/llvm/utils/lit/tests/Inputs/show-used-features/lit.cfg b/llvm/utils/lit/tests/Inputs/show-used-features/lit.cfg
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/show-used-features/lit.cfg
@@ -0,0 +1,6 @@
+import lit.formats
+config.name = 'show-used-features'
+config.suffixes = ['.txt']
+config.test_format = lit.formats.ShTest()
+config.test_source_root = None
+config.test_exec_root = None
diff --git a/llvm/utils/lit/tests/Inputs/show-used-features/mixed.txt b/llvm/utils/lit/tests/Inputs/show-used-features/mixed.txt
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/show-used-features/mixed.txt
@@ -0,0 +1,4 @@
+
+// REQUIRES: my-require-feature-2 || my-require-feature-3
+// UNSUPPORTED: my-unsupported-feature-2, my-unsupported-feature-3
+// XFAIL: my-xfail-feature-2, my-xfail-feature-3
diff --git a/llvm/utils/lit/tests/Inputs/show-used-features/requires.txt b/llvm/utils/lit/tests/Inputs/show-used-features/requires.txt
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/show-used-features/requires.txt
@@ -0,0 +1,2 @@
+
+// REQUIRES: my-require-feature-1
diff --git a/llvm/utils/lit/tests/Inputs/show-used-features/unsupported.txt b/llvm/utils/lit/tests/Inputs/show-used-features/unsupported.txt
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/show-used-features/unsupported.txt
@@ -0,0 +1,2 @@
+
+// UNSUPPORTED: my-unsupported-feature-1
diff --git a/llvm/utils/lit/tests/Inputs/show-used-features/xfail.txt b/llvm/utils/lit/tests/Inputs/show-used-features/xfail.txt
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/show-used-features/xfail.txt
@@ -0,0 +1,2 @@
+
+// XFAIL: my-xfail-feature-1
diff --git a/llvm/utils/lit/tests/show-used-features.py b/llvm/utils/lit/tests/show-used-features.py
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/show-used-features.py
@@ -0,0 +1,6 @@
+# Check that --show-used-features works correctly.
+#
+# RUN: %{lit} %{inputs}/show-used-features --show-used-features | FileCheck %s
+# CHECK: my-require-feature-1 my-require-feature-2 my-require-feature-3
+# CHECK: my-unsupported-feature-1 my-unsupported-feature-2 my-unsupported-feature-3
+# CHECK: my-xfail-feature-1 my-xfail-feature-2 my-xfail-feature-3