Implement getPassName() for IR printing passes.

llvm-svn: 297442
diff --git a/llvm/lib/Analysis/LoopPass.cpp b/llvm/lib/Analysis/LoopPass.cpp
index 3f4a079..0b5f6266 100644
--- a/llvm/lib/Analysis/LoopPass.cpp
+++ b/llvm/lib/Analysis/LoopPass.cpp
@@ -54,6 +54,8 @@
     }
     return false;
   }
+
+  StringRef getPassName() const override { return "Print Loop IR"; }
 };
 
 char PrintLoopPassWrapper::ID = 0;