-targets = set(config.root.targets_to_build.split())
-if not 'SystemZ' in targets:
+if not 'SystemZ' in config.root.targets:
config.unsupported = True
+# http://llvm.org/bugs/show_bug.cgi?id=20980
+if 'ubsan' in config.available_features:
+ config.unsupported = True