Fix a bunch of unused variable warnings when doing a release
build with gcc-4.6.

llvm-svn: 142350
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 632b614..df94e0f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2800,6 +2800,7 @@
             EVT.getVectorNumElements() == VT.getVectorNumElements()) &&
            "Vector element counts must match in FP_ROUND_INREG");
     assert(EVT.bitsLE(VT) && "Not rounding down!");
+    (void)EVT;
     if (cast<VTSDNode>(N2)->getVT() == VT) return N1;  // Not actually rounding.
     break;
   }