Fix a bunch of places where operator-> was used directly on the return from dyn_cast.

Inspired by r331508, I did a grep and found these.

Mostly just change from dyn_cast to cast. Some cases also showed a dyn_cast result being converted to bool, so those I changed to isa.

llvm-svn: 331577
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 55e82d6..14a9638 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -4257,9 +4257,9 @@
     if (!Op.isUndef()) {
       uint64_t Value;
       if (Op.getOpcode() == ISD::Constant)
-        Value = dyn_cast<ConstantSDNode>(Op)->getZExtValue();
+        Value = cast<ConstantSDNode>(Op)->getZExtValue();
       else if (Op.getOpcode() == ISD::ConstantFP)
-        Value = (dyn_cast<ConstantFPSDNode>(Op)->getValueAPF().bitcastToAPInt()
+        Value = (cast<ConstantFPSDNode>(Op)->getValueAPF().bitcastToAPInt()
                  .getZExtValue());
       else
         return false;
@@ -4642,7 +4642,7 @@
       Op1.getOpcode() != ISD::BITCAST &&
       Op1.getOpcode() != ISD::ConstantFP &&
       Op2.getOpcode() == ISD::Constant) {
-    uint64_t Index = dyn_cast<ConstantSDNode>(Op2)->getZExtValue();
+    uint64_t Index = cast<ConstantSDNode>(Op2)->getZExtValue();
     unsigned Mask = VT.getVectorNumElements() - 1;
     if (Index <= Mask)
       return Op;