Reduce dyn_cast<> to isa<> or cast<> where possible.

No functional change intended.

llvm-svn: 234586
diff --git a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
index 150dac3..a9ffa72 100644
--- a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -626,7 +626,7 @@
   // Add a leading constant argument with the Flags and the calling convention
   // masked together
   CallingConv::ID CallConv = CS.getCallingConv();
-  int Flags = dyn_cast<ConstantInt>(CS.getArgument(2))->getZExtValue();
+  int Flags = cast<ConstantInt>(CS.getArgument(2))->getZExtValue();
   assert(Flags == 0 && "not expected to be used");
   Ops.push_back(DAG.getTargetConstant(StackMaps::ConstantOp, MVT::i64));
   Ops.push_back(