diff --git a/test/Transforms/CorrelatedValuePropagation/basic.ll b/test/Transforms/CorrelatedValuePropagation/basic.ll
index b210d37f1b8..9a9fc0f639d 100644
--- a/test/Transforms/CorrelatedValuePropagation/basic.ll
+++ b/test/Transforms/CorrelatedValuePropagation/basic.ll
@@ -16,6 +16,7 @@ exit:           ; preds = %0
         ret i32 10
 }
 
+; PR4420
 declare i1 @ext()
 ; CHECK: @test2
 define i1 @test2() {