tblgen: Replace uses of dynamic_cast<XXXRecTy> with dyn_cast<>.

This is a mechanical change of dynamic_cast<> to dyn_cast<>. A number of
these uses are actually more like isa<> or cast<>, and will be changed
to the semanticaly appropriate one in a future patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165291 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/FixedLenDecoderEmitter.cpp b/utils/TableGen/FixedLenDecoderEmitter.cpp
index e755c1c..b5f62d8 100644
--- a/utils/TableGen/FixedLenDecoderEmitter.cpp
+++ b/utils/TableGen/FixedLenDecoderEmitter.cpp
@@ -1758,7 +1758,7 @@
     // FIXME: This need to be extended to handle instructions with custom
     // decoder methods, and operands with (simple) MIOperandInfo's.
     TypedInit *TI = dynamic_cast<TypedInit*>(NI->first);
-    RecordRecTy *Type = dynamic_cast<RecordRecTy*>(TI->getType());
+    RecordRecTy *Type = dyn_cast<RecordRecTy>(TI->getType());
     Record *TypeRecord = Type->getRecord();
     bool isReg = false;
     if (TypeRecord->isSubClassOf("RegisterOperand"))