Add DAG parameter to ComputeNumSignBitsForTargetNode

This way, you can check the number of sign bits in the
operands. The depth parameter it already has is pretty useless
without this.

llvm-svn: 205649
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 5de0b03..8948467 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1074,6 +1074,7 @@
 /// targets that want to expose additional information about sign bits to the
 /// DAG Combiner.
 unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
+                                                         const SelectionDAG &,
                                                          unsigned Depth) const {
   assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
           Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||