Simplify some logic in ComputeMaskedBits. And change ComputeMaskedBits
to pass the mask APInt by value, not by reference. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47096 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/CellSPU/SPUISelLowering.cpp b/lib/Target/CellSPU/SPUISelLowering.cpp
index 6fe6e48..f6e3359 100644
--- a/lib/Target/CellSPU/SPUISelLowering.cpp
+++ b/lib/Target/CellSPU/SPUISelLowering.cpp
@@ -2668,7 +2668,7 @@
 
 void
 SPUTargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
-                                                  APInt Mask,
+                                                  const APInt &Mask,
                                                   APInt &KnownZero, 
                                                   APInt &KnownOne,
                                                   const SelectionDAG &DAG,