diff --git a/llvm/utils/lit/lit/llvm/config.py b/llvm/utils/lit/lit/llvm/config.py
--- a/llvm/utils/lit/lit/llvm/config.py
+++ b/llvm/utils/lit/lit/llvm/config.py
@@ -9,10 +9,6 @@
 from lit.llvm.subst import ToolSubst
 
 
-def binary_feature(on, feature, off_prefix):
-    return feature if on else off_prefix + feature
-
-
 class LLVMConfig(object):
 
     def __init__(self, lit_config, config):
@@ -73,13 +69,12 @@
         # Sanitizers.
         sanitizers = getattr(config, 'llvm_use_sanitizer', '')
         sanitizers = frozenset(x.lower() for x in sanitizers.split(';'))
-        features.add(binary_feature('address' in sanitizers, 'asan', 'not_'))
-        features.add(binary_feature('memory' in sanitizers, 'msan', 'not_'))
-        features.add(binary_feature(
-            'undefined' in sanitizers, 'ubsan', 'not_'))
+        features.add('asan' if 'address' in sanitizers else 'not_asan')
+        features.add('msan' if 'memory' in sanitizers else 'not_msan')
+        features.add('ubsan' if 'undefined' in sanitizers else 'not_ubsan')
 
         have_zlib = getattr(config, 'have_zlib', None)
-        features.add(binary_feature(have_zlib, 'zlib', 'no'))
+        features.add('zlib' if have_zlib else 'nozlib')
 
         # Check if we should run long running tests.
         long_tests = lit_config.params.get('run_long_tests', None)