Fix -Asserts warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103694 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/NEONPreAllocPass.cpp b/lib/Target/ARM/NEONPreAllocPass.cpp
index 766a9b9..6c43e69 100644
--- a/lib/Target/ARM/NEONPreAllocPass.cpp
+++ b/lib/Target/ARM/NEONPreAllocPass.cpp
@@ -344,6 +344,7 @@
   MachineOperand &FMO = MI->getOperand(FirstOpnd);
   assert(FMO.isReg() && FMO.getSubReg() == 0 && "unexpected operand");
   unsigned VirtReg = FMO.getReg();
+  (void)VirtReg;
   assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
          "expected a virtual register");
   if (FMO.isDef()) {