[TableGen] Replace static_cast with llvm's cast. NFC

These all appear next to an isa<> and cast<> is much more
common in these cases.

Author: topperc

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

@@ -1632,12 +1632,12 @@ bool SDTypeConstraint::ApplyTypeConstraint(TreePatternNode *N,
     // have an integer type that is smaller than the VT.
     if (!NodeToApply->isLeaf() ||
         !isa<DefInit>(NodeToApply->getLeafValue()) ||
-        !static_cast<DefInit*>(NodeToApply->getLeafValue())->getDef()
+        !cast<DefInit>(NodeToApply->getLeafValue())->getDef()
                ->isSubClassOf("ValueType")) {
       TP.error(N->getOperator()->getName() + " expects a VT operand!");
       return false;
     }
-    DefInit *DI = static_cast<DefInit*>(NodeToApply->getLeafValue());
+    DefInit *DI = cast<DefInit>(NodeToApply->getLeafValue());
     const CodeGenTarget &T = TP.getDAGPatterns().getTargetInfo();
     auto VVT = getValueTypeByHwMode(DI->getDef(), T.getHwModes());
     TypeSetByHwMode TypeListTmp(VVT);
@@ -3832,7 +3832,7 @@ void CodeGenDAGPatterns::parseInstructionPattern(
     InstInputs.erase(OpName);   // It occurred, remove from map.
 
     if (InVal->isLeaf() && isa<DefInit>(InVal->getLeafValue())) {
-      Record *InRec = static_cast<DefInit*>(InVal->getLeafValue())->getDef();
+      Record *InRec = cast<DefInit>(InVal->getLeafValue())->getDef();
       if (!checkOperandClass(Op, InRec))
         I.error("Operand $" + OpName + "'s register class disagrees"
                  " between the operand and pattern");