diff --git a/llvm/utils/lit/lit/cl_arguments.py b/llvm/utils/lit/lit/cl_arguments.py
index e03e4c269d725c..06b1313cb8bb1a 100644
--- a/llvm/utils/lit/lit/cl_arguments.py
+++ b/llvm/utils/lit/lit/cl_arguments.py
@@ -58,10 +58,7 @@ def parse_args():
             help="Display all commandlines and output",
             action="store_true")
     format_group.add_argument("-o", "--output",
-            dest="reports",
-            action="append",
             type=lit.reports.JsonReport,
-            default=[],
             help="Write test results to the provided path",
             metavar="PATH")
     format_group.add_argument("--no-progress-bar",
@@ -102,10 +99,7 @@ def parse_args():
             help="Don't execute any tests (assume PASS)",
             action="store_true")
     execution_group.add_argument("--xunit-xml-output",
-            dest="reports",
-            action="append",
             type=lit.reports.XunitReport,
-            default=[],
             help="Write XUnit-compatible XML test reports to the specified file")
     execution_group.add_argument("--timeout",
             dest="maxIndividualTestTime",
@@ -190,6 +184,8 @@ def parse_args():
     else:
         opts.shard = None
 
+    opts.reports = filter(None, [opts.output, opts.xunit_xml_output])
+
     return opts