Use isa<> instead of dyn_cast<> as suggested by Nick.
Should've read the patch a bit closer, sorry.

llvm-svn: 144164
diff --git a/llvm/tools/llvm-diff/DiffConsumer.cpp b/llvm/tools/llvm-diff/DiffConsumer.cpp
index 24b372d..d9e1814 100644
--- a/llvm/tools/llvm-diff/DiffConsumer.cpp
+++ b/llvm/tools/llvm-diff/DiffConsumer.cpp
@@ -64,7 +64,7 @@
     }
     return;
   }
-  if (dyn_cast<Constant>(V)) {
+  if (isa<Constant>(V)) {
     out << *V;
     return;
   }