[XCore] Simplify code that checks for an aligned base plus a constant.

The code now makes use of ComputeMaskedBits,
SelectionDAG::isBaseWithConstantOffset and TargetLowering::isGAPlusOffset
where appropriate reducing the amount of logic needed in XCoreISelLowering.
No intended functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181125 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreISelLowering.h

@@ -135,6 +135,9 @@ namespace llvm {
     SDValue getReturnAddressFrameIndex(SelectionDAG &DAG) const;
     SDValue getGlobalAddressWrapper(SDValue GA, const GlobalValue *GV,
                                     SelectionDAG &DAG) const;
+    SDValue lowerLoadWordFromAlignedBasePlusOffset(DebugLoc DL, SDValue Chain,
+                                                   SDValue Base, int64_t Offset,
+                                                   SelectionDAG &DAG) const;
 
     // Lower Operand specifics
     SDValue LowerLOAD(SDValue Op, SelectionDAG &DAG) const;