Index: llvm/test/lit.cfg.py
===================================================================
--- llvm/test/lit.cfg.py
+++ llvm/test/lit.cfg.py
@@ -329,10 +329,11 @@
                                       stdout=subprocess.PIPE)
     except OSError:
         print('Could not exec sysctl')
-    result = sysctl_cmd.stdout.read().decode('ascii')
-    if -1 != result.find('hw.optional.fma: 1'):
-        config.available_features.add('fma3')
-    sysctl_cmd.wait()
+    else:
+        result = sysctl_cmd.stdout.read().decode('ascii')
+        if -1 != result.find('hw.optional.fma: 1'):
+            config.available_features.add('fma3')
+        sysctl_cmd.wait()
 
 # .debug_frame is not emitted for targeting Windows x64.
 if not re.match(r'^x86_64.*-(windows-gnu|windows-msvc)', config.target_triple):