tblgen: Mechanically move dynamic_cast<> to dyn_cast<>.

Some of these dyn_cast<>'s would be better phrased as isa<> or cast<>.
That will happen in a future patch.

There are also two dyn_cast_or_null<>'s slipped in instead of
dyn_cast<>'s, since they were causing crashes with just dyn_cast<>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165646 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/FastISelEmitter.cpp b/utils/TableGen/FastISelEmitter.cpp
index ca784d0..c6d71ff 100644
--- a/utils/TableGen/FastISelEmitter.cpp
+++ b/utils/TableGen/FastISelEmitter.cpp
@@ -245,7 +245,7 @@
       if (Op->getType(0) != VT)
         return false;
 
-      DefInit *OpDI = dynamic_cast<DefInit*>(Op->getLeafValue());
+      DefInit *OpDI = dyn_cast<DefInit>(Op->getLeafValue());
       if (!OpDI)
         return false;
       Record *OpLeafRec = OpDI->getDef();
@@ -406,7 +406,7 @@
   if (!Op->isLeaf())
     return PhysReg;
 
-  DefInit *OpDI = dynamic_cast<DefInit*>(Op->getLeafValue());
+  DefInit *OpDI = dyn_cast<DefInit>(Op->getLeafValue());
   Record *OpLeafRec = OpDI->getDef();
   if (!OpLeafRec->isSubClassOf("Register"))
     return PhysReg;
@@ -473,7 +473,7 @@
       // a bit too complicated for now.
       if (!Dst->getChild(1)->isLeaf()) continue;
 
-      DefInit *SR = dynamic_cast<DefInit*>(Dst->getChild(1)->getLeafValue());
+      DefInit *SR = dyn_cast<DefInit>(Dst->getChild(1)->getLeafValue());
       if (SR)
         SubRegNo = getQualifiedName(SR->getDef());
       else