implement the new addressing mode description hook.

llvm-svn: 35521
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index e66d165..593400c 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -236,6 +236,10 @@
     SDOperand isOperandValidForConstraint(SDOperand Op, char ConstraintLetter,
                                           SelectionDAG &DAG);
 
+    /// isLegalAddressingMode - Return true if the addressing mode represented
+    /// by AM is legal for this target, for a load/store of the specified type.
+    virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty)const;
+    
     /// isLegalAddressImmediate - Return true if the integer value can be used
     /// as the offset of the target addressing mode for load / store of the
     /// given type.