Replace dyn_cast<> with cast<> since the cast is already guarded by the necessary check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133874 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bab15e6..0810267 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2506,7 +2506,7 @@
       return false;
     FI = FINode->getIndex();
   } else if (Arg.getOpcode() == ISD::FrameIndex && Flags.isByVal()) {
-    FrameIndexSDNode *FINode = dyn_cast<FrameIndexSDNode>(Arg);
+    FrameIndexSDNode *FINode = cast<FrameIndexSDNode>(Arg);
     FI = FINode->getIndex();
     Bytes = Flags.getByValSize();
   } else