Silence warnings in non assert builds. Patch by David Blaikie

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133118 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index fd90731..c42054e 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -1550,8 +1550,8 @@
 
 SDValue MipsTargetLowering::
 LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
-  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
-  assert((Depth == 0) &&
+  // check the depth
+  assert((cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() == 0) &&
          "Frame address can only be determined for current frame.");
 
   MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();