[mips] Use isa<> instead of dyn_cast<> with unused value. NFC.

Reviewers: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7615

llvm-svn: 229138
diff --git a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
index daeb20c..e180cb0 100644
--- a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -2291,9 +2291,9 @@
 static bool isConstantOrUndef(const SDValue Op) {
   if (Op->getOpcode() == ISD::UNDEF)
     return true;
-  if (dyn_cast<ConstantSDNode>(Op))
+  if (isa<ConstantSDNode>(Op))
     return true;
-  if (dyn_cast<ConstantFPSDNode>(Op))
+  if (isa<ConstantFPSDNode>(Op))
     return true;
   return false;
 }